Service Manual
NPE Condensing Water Heaters
Getting Service
If your water heater requires service, you have several options for getting service:
●● Contact Technical Support at 1-800-519-8794 or on the website: www.navien.com.
- For Navien Service Specialists(NSS) ONLY, please have your 6-digit NSS ID Number ready
and use the available NSS hotlline at 1-877-670-5122.
* Refer to the website: http://us.navien.com/BecomeNSS.
●● Contact the technician or professional who installed your water heater.
●● Contact a licensed professional for the affected system (for example, a plumber or electrician).
When you contact Technical Support, please have the following information at hand:
Model number
●● Serial number
●● Date purchased
●● Installation location and type
●● Error code, if any appears on the front panel display.
●●
Version : 2.30 (Nov. 08. 2016)
Navien, Inc.
800.519.8794 www.Navien.com
20 Goodyear lrvine, CA 92618
T H E
L E A D E R
I N
Downloaded from www.Manualslib.com manuals search engine
C O N D E N S I N G
T E C H N O L O G Y
Service Manual
NPE Condensing Water Heaters
Model
NPE-180A
NPE-210A
NPE-240A
NPE-150S
NPE-180S
NPE-210S
NPE-240S
NSF/ANSI 372
Keep this manual near this water heater for future
reference whenever maintenance or service is required.
* The wetted surface of this product contacted by consumable water contains less than
one quarter of one percent (0.25%) of lead by weight.
WARNING
If the information in these instructions is not followed exactly, a fire or explosion may result, causing
property damage, personal injury or death.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this
or any other appliance.
What to do if you smell gas
●● Do not try to light any appliance
●● Do not touch any electrical switch; do not use any phone in your building
●● Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
●● If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency or the gas supplier.
The installation must conform with local codes or, in the absence of local codes, the National Fuel Gas
Code, ANSIZ223.1/NFPA 54 and/or CSA B149.1, Natural Gas and Propane Installation Code.
When applicable, the installation must conform with the Manufactured Home Construction and
Safety Standard, Title 24 CFR, Part 3280 and/or CAN/CSA Z240 MH Series, Mobile Homes.
Downloaded from www.Manualslib.com manuals search engine
Downloaded from www.Manualslib.com manuals search engine
Revisions
Version
Description of changes
Date
1.00
First Issue
September/31/12
1.01
Specification change (PCB)
April/19/13
2.00
Additional models (NPE-180S, 210S, 240S)
July/22/13
2.10
Additional funtion (Front Panel)
September/12/13
2.20
Additional sub error code list and Supplement of ComfortAir+ Manual
April/14/14
2.21
NPE-S Energy factor change
November/24/14
2.22
Additional models (NPE-150S)
July/11/15
2.30
Warranty Change, Add NSS Hotline Number
November/8/16
2.22 Reviewed by:Albert Choi
Revisions
Downloaded from www.Manualslib.com manuals search engine
3
Contents
1. Safety Information
8
1.1
1.2
1.3
1.4
8
8
8
8
Safety Definitions
Safety Symbols
Symbols Used in the Instructions
Safety Precautions
2. Product Information
12
2.1 Product Information
2.2 Layout and Key Components
12
13
3. Technical Data
16
3.1 General Specifications
3.2 Dimensions
16
17
4. System Details
18
4.1 Schematic and Flow Diagram
4.2 Operation Flow Chart
4.3 Setting the DIP Switches
4.4 Measuring the Inlet Gas Pressure
4.5 Selecting a Recirculation Mode
4.6 Gas Conversion
4.7 The Front Panel
4.8 Wiring Diagram
4.9 Ladder Diagram
4.10 Electrical Diagnostic Points
4.11 Key Components Description
18
20
21
24
27
29
34
52
54
56
58
4.11.1 PCB
4.11.2 High Limit Switch 4.11.3 Thermistor
4.11.4 Fan Motor
4.11.5 Flame Rod Assembly
4.11.6 Ignition Transformer
4.11.7 APS
4.11.8 Main Gas Valve
4.11.9 Burner
4.11.10 Water Adjustment Valve
4.11.11 Flow Sensor
4.11.12 Primary Heat Exchanger
4.11.13 Secondary Heat Exchanger
4.11.14 Buffer Tank (“A” models only)
4.11.15 Circulation Pump (“A” models only)
4
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
5. Troubleshooting
73
5.1 Error Code List
73
5.1.1 003Error
5.1.2 004Error
5.1.3 012Error
5.1.4 016Error
5.1.5 030Error
5.1.6 046Error
5.1.7 047Error
5.1.8 060Error
5.1.9 109Error
5.1.10 110Error
5.1.11 407Error
76
81
83
88
91
93
93
94
96
98
99
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
5.1.12
5.1.13
5.1.14
5.1.15
5.1.16
5.1.17
5.1.18
5.1.19
5.1.20
5.1.21
5.1.22
5.1.23
5.1.24
5.1.25
5.1.26
5.1.27
5.1.28
421Error
432Error
434Error
438Error ("A" models only)
439Error
441Error
445Error
515Error
517Error
593Error
594Error
615Error
736Error
782Error
740Error
760Error
785Error
100
101
102
105
107
110
110
113
114
114
115
115
116
116
117
117
117
5.2 Troubleshooting guide by symptom
118
6. Replacement of Parts
121
6.1 Replacement Procedure
6.2 Components Replacement Instructions
121
121
7. Components Diagram and Part List
7.1
7.2
7.3
7.4
7.5
7.6
Case Assembly Burner Assembly(NPE-180A/ 210A/ 240A)
Burner Assembly(NPE-150S/ 180S/ 210S/ 240S)
Waterway Assembly(NPE-150S/ 180S/ 210S/ 240S)
Waterway Assembly(NPE-150S/ 180S/ 210S/ 240S)
Fan(Gas) Assembly
8. Inspection and Maintenance Schedule
8.1
8.2
8.3
8.4
133
Maintenance
Annual Servicing
Inspection Report
Maintenance Report
133
135
137
139
141
143
145
145
149
150
150
9. Common Vent and Outdoor vent Cover Installing
151
9.1
9.2
9.3
9.4
9.5
9.6
Installing the Outdoor vent Cover
Installing Procedure
Choosing an Installation Location
Mounting Water Heater
Ventilation Flow
Common Venting
10. Installing the H2Air+
10.1
10.2
10.3
10.4
10.5
10.6
10.7
About the H2Air+
Installing the Device
Wiring the Device
Configuring the Device
Configuring the NPE-180A/240A Water Heater
Maintenance
Appendix
151
152
153
154
155
156
158
158
159
161
163
164
170
170
Version 2.21
Navien Warranty
Warranty Period
Warranty Service
Navien products come with a limited warranty covering labor,
parts and the heat exchanger. The following warranty periods
begin to run from the date of original installation. The date of
original installation must be provided to Navien, and upon request,
proof of the original installation date must also be provided to
Navien. When the product is installed in a new construction, the
commencement date shall be dated upon which the end-user
takes title to the property.
At its option, Navien will replace the defective component (part(s)
or heat exchanger), in accordance with the terms of this Limited
Warranty, if it fails in normal use and service during the Applicable
Warranty Period identified above. The replacement component
must be Navien original factory component. Navien, at its sole
discretion, may replace the product with a new or refurbished
product of comparable quality and design. The replacement
component or product will be warranted only for the unexpired
portion of the original component’s Applicable Warranty Period.
Payment for labor in completing the warranty service is subject
to Navien’s prior written approval and shall be subject to Navien’s
schedule of approved labor allowances.
APPLICABLE WARRANTY PERIOD
Labor
Warranty
Product
Standard or
NPE Series
Water Heater
(Residential )
NPE Series
Water Heater
(Commercial
or Combi1)
1 Year
2
Cont.-Recirc.
Parts
Warranty
5 years
Heat
Exchanger
Warranty
15 Years
Warranty Exclusions
Navien’s Limited Warranty shall be void in the event of an
occurrence of any of the following:
●●
3
Uncont.-Recirc.
Standard or
2
Cont.-Recirc .
3
Uncont.-Recirc.
1 Year
3 Years
5 Years
1 Year
5 years
8 Years
1 Year
3 Years
3 Years
1Combi refers to a combination potable water and space heating
application. Water heaters cannot be used in space heating only
applications.
●●
●●
●●
2Controlled-Recirculation:
Recirculation through the water heater is controlled by
either the water heater or an external aquastat.
3Uncontrolled-Recirculation:
External pumps configured to circulate continuously
through the water heater are subject to the uncontrolled
recirculation warranty terms. An aquastat is the minimum
pump control requirement for DHW or storage tank
recirculation in order to maintain the full controlled
recirculation warranty.
Warranty Claim Procedures
To obtain warranty repair service, the end user or homeowner
must contact the original installer of your Navien product. If the
original installer cannot be identified, the end user or homeowner
may contact Navien’s Technical Administration Department at
(800) 519-8794. Proof of purchase is required to obtain warranty
service.
●●
●●
●●
●●
●●
●●
Improper installation, failure to install in strict compliance with
the Installation Manual procedures, installed by a non-licensed
installer, and installation in violation of applicable rules, laws or
building codes.
Product purchased through the internet, other e-commerce
channels, or any installer that obtained the Product from a
supplier or distributor not authorized by Navien.
Failure to perform regular maintenance, misuse, operation at
settings other than those recommended or specified, noncompliance with instructions or guidelines set forth in the User’s
Operation Manual.
Modification or alteration of the Product in any manner,
including but not limited to, removal of any component or
part, addition of any non-approved components, relocating
or moving the Product from its original installation site, or any
accidental or intentional damage to the Product.
Installation for non-recommended uses.
Any damage caused by local adverse conditions including but
not limited to hard water deposits, lime or mineral build-up,
operating in corrosive atmospheric elements.
Damage or problems caused by gas flow issues, electrical surges,
flooding, fire, abnormal external temperature, and any other
cause of damage not directly caused by a manufacturing defect.
Installer’s failure to fully comply with the Warranty Service and
Return Policy procedures previously provided to Installer and
as is available on Navien’s website. Such policies include but
are not limited to the Installer’s failure to first contact Navien
Technical Support while in front of the product for purposes of
trouble shooting the identified problem or issue.
Use of the NPE Series Water Heater for space heating only
purposes shall void the warranty.
Heat exchanger failures (leaks) caused by operating the water
heater in a corrosive or contaminated atmosphere or damages,
malfunctions or failures caused by lime, mineral build-up, or
scale will not cover.
5
Downloaded from www.Manualslib.com manuals search engine
●●
●●
●●
●●
●●
●●
●●
●●
●●
Performance problems caused by improper sizing of the water
heater, the gas supply line, the venting connection, combustion
air openings, electric service voltage, wiring, fusing or any other
components, parts or specifications.
Improper conversion from natural gas to LP gas or LP gas
to natural gas or attempt to operate with a type of gas not
specified for the water heater.
Any damage, malfunction or failure caused by abuse,
negligence, alteration, accident, fire, flood, freezing, wind,
lightning and other acts of God.
Operating, using or storing the water heater in a corrosive or
contaminated atmosphere or environment.
Operating the water heater at water temperatures outside the
factory calibrated temperature limits and/or exceeding the
maximum setting of the high limit control.
Operating the water heater when it is not supplied with potable
water at all times.
Subjecting the heat exchanger to pressures or firing rates
greater or lesser than those shown on the rating plate.
Installation at any location outside the United States and
Canada.
Removal or alteration of the rating plate.
Other Terms: This Limited Warranty is subject further to the terms
and conditions set forth herein and as may be further specified
in the Terms and Conditions page located on Navien’s website
at www.navien.com. WITH THE EXCEPTION OF THIS LIMITED
WARRANTY, NAVIEN DISCLAIMS ANY OBLIGATION OR LIABILITY
WITH RESPECT TO THE PRODUCTS OR THEIR SALE AND USE, AND
NAVIEN NEITHER ASSUMES NOR AUTHORIZES THE ASSUMPTION
OF, ANY OBLIGATION OR LIABILITY IN CONNECTION WITH THE
PRODUCTS. THIS DISCLAIMER INCLUDES ANY OTHER WARRANTIES,
EXPRESS, IMPLIED OR STATUTORY RESPECTING THE PRODUCTS
OR ANY PARTS OR COMPONENTS THEREOF, INCLUDING, BUT NOT
LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE. Navien’s total liability
for any claim arising hereunder shall not exceed the purchase
price which you paid for the Product. NAVIEN SHALL NOT IN ANY
EVENT BE LIABLE FOR INDIRECT, SPECIAL, CONSEQUENTIAL OR
LIQUIDATED DAMAGES OR PENALTIES, INCLUDING CLAIMS FOR
LOST REVENUE, PROFITS OR BUSINESS OPPORTUNITIES, EVEN IF
NAVIEN HAD OR SHOULD HAVE HAD ANY KNOWLEDGE, ACTUAL
OR CONSTRUCTIVE, OF THE POSSIBILITY OF SUCH DAMAGES.
This Limited Warranty does not cover any product used in an
application that uses chemically treated water such as a pool or
spa heater.
6
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Abbreviations and Definitions
Abbreviation
Definition
NPE
General name of NPE-180A, NPE-210A, NPE-240A, NPE-150S, NPE-180S, NPE-210S, and NPE-240S
NG
Natural Gas
LP
Propane Gas
AP
Air Pressure
APS
Air Pressure Sensor
DHW
Domestic Hot Water
FM
Fan Motor
GARC
Gas Air Ratio Control
GPM
Gallons Per Minute
GV
Gas Valve : Main and Solenoid
MGV
Main Gas Valve
RPM
Revolutions Per Minute
WAV
Water Adjustment Valve
PCB
Printed Circuit Board
EMI
Electromagnetic Interface
HTL
High Temperature Limiter
7
Downloaded from www.Manualslib.com manuals search engine
1. Safety Information
1.1 Safety Definitions
1.3 Symbols Used in the Instructions
All Safety messages indicate the risk of potential hazards. Follow the
instructions precisely to avoid the risk of injury.
The following symbols are used throughout the instructions to
bring attention to important information concerning the appliance.
This is the safety alert symbol. It is used
to alert you of potential personal injury
hazards.
Observe all of the safety messages that
follow this symbol to avoid possible injury
or death.
IMPORTANT
Warns of a risk of damage and environmental pollution
NOTE
1.2 Safety Symbols
DANGER
Indicates an imminently hazardous situation which, if not
avoided, could result in severe injury or death.
Indicates additional information that is important but not
related to personal injury or property damage.
1.4 Safety Precautions
DANGER
WARNING
Indicates a potentially hazardous situation which, if not
avoided, could result in injury or death.
CAUTION
Indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury.
8
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
FLAMMABLE MATERIALS
Keep the area around the water heater clear and free from
flammable materials.
●●
DO NOT place flammable liquids such as oils or gasoline, etc.
near the water heater.
●●
DO NOT place combustibles such as newspapers and
laundry etc. near the water heater or the venting system.
●●
DO NOT place or use hair spray, spray paint or any other type
of spray can near the water heater or the venting system
(including the vent termination).
●●
DO NOT place anything in or around the vent terminations
that could obstruct the air flow in and out of the water
heater such as a clothes line.
Version 2.21
DANGER
DANGER
HOT WATER TEMPERATURE SETTING
FLAMMABLE VAPORS
Vapors from flammable liquids will explode and catch fire
causing death or severe burns.
Do not use or store flammable products such as gasoline,
solvents or adhesives in the same room or area near the water
heater.
●●
●●
●●
Keep flammable products: far away from the water heater
in approved containers, tightly closed, and out of children’s
reach.
Water heater has a main burner flame: which can come on
at any time, and may ignite flammable vapors.
Vapors: cannot be seen, are heavier than air, go a long way
on the floor and can be carried from other rooms to the
main burner flame by air currents.
DANGER
COMPROMISED VENTING SYSTEM
●●
Failure to follow the Venting Section of the installation
manual may result in unsafe operation of this water heater.
To avoid the risk of fire, explosion or asphyxiation from
carbon monoxide, never operate the water heater unless it
is properly vented to the outside and has an adequate air
supply for proper operation.
●●
Be sure to inspect the vent termination and the air intake
pipe annually to ensure safe operation of the water heater.
●●
Immediately turn off and do not use the water heater if any
of the vent pipes, vent elbows and/or the water heater are:
-- damaged in any way;
-- separated at a joint,
-- cracked or show evidence of corrosion, rusting or
melting.
●●
Water temperatures at or above 125°F (52°C) can cause
severe burns instantly or death from scalds.
●●
Households with small children, disabled, or elderly persons
may require 120 °F (49°C) or lower temperature setting to
prevent contact with “HOT” water.
DANGER
WHAT TO DO IF YOU SMELL GAS
If you do not follow these instructions exactly, a fire or
explosion may result causing property damage, personal
injury or loss of life.
DO NOT OPERATE THE WATER HEATER.
DO NOT OPERATE ANY FAUCETS.
Smell all around the appliance area for gas. Be sure to smell
next to the floor because some gas is heavier than air and will
settle on the floor.
●●
Do not smoke.
●●
Extinguish any open flames and sparks.
●●
Do not operate light switches or electrical equipment
switches.
●●
Do not use any phone in your building.
●●
Open the windows and doors.
●●
Close the gas shutoff valve.
●●
Keep people away from the danger zone.
●●
Observe the safety regulations of your local gas supplier,
found on the gas meter.
●●
Immediately call your gas supplier from the outside of the
building. Follow the gas supplier’s instructions.
●●
If you cannot reach your gas supplier, call the fire department.
●●
Notify your plumbing/heating contractor from the outside
of the building.
Safety Information
Downloaded from www.Manualslib.com manuals search engine
9
DANGER
DANGER
IMPORTANT SAFETY PREAUTIONS
HOT
●●
Read and understand this safety information before
operating or servicing this Navien Water Heater.
●●
Confirm the location of the gas shut-off valve. Close the
manual shut-off valve if the Navien Water Heater ever
becomes subjected to overheating, fire, flood, physical
damage or any other such damaging condition during
servicing.
●●
DO NOT turn on the water heater unless water and gas
supplies are fully opened.
●●
DO NOT turn on the water heater if the cold water supply
shut-off valve is closed.
●●
Make certain power to the water heater is “OFF” before
removing the front cover for any reason.
●●
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and dangerous
operation. Verify proper operation after servicing.
●●
Improper adjustment, alteration, service or maintenance
can cause property damage, personal injury, or death.
●●
To prevent scalding, always check the temperature of the
hot water after servicing.
●●
DO NOT attempt to change the water temperature while
someone is using the water heater.
●●
DO NOT use parts other than those specified for this
equipment.
●●
DO NOT operate the water heater if you feel something is
wrong with the unit.
●●
DO NOT allow children to operate or otherwise handle the
unit.
BURN
HOT WATER TEMPERATURE SETTING
●●
Water temperatures at or above 125°F (52°C) can cause
severe burns instantly or death from scalds.
●●
Households with small children, disabled, or elderly persons
may require 120°F (49°C) or lower temperature setting to
prevent contact with “HOT” water.
●●
To prevent scalding, check water temperature after servicing.
●●
If the proposed water heater outlet temperature is at or
above 125°F (52°C), a thermostatically controlled mixing
valve or temperature limiting valve should be considered to
reduce the risk of scalding. Contact a licensed plumber or
the local plumbing authority for further information.
●●
This Navien Water Heater is factory set at 120°F (49°C) for
your safety and comfort. Increasing the set temperature
increases the risk of accidental scalding. Consult the chart
below before you decide to adjust the set temperature.
Water Temperature
10
Time in which a young child can suffer
a full thickness (3rd degree) burn
70 °C (160°F)
Less than 1 second
60 °C (140°F)
1 second
55 °C (130°F)
10 second
49 °C (120°F)
10 minutes
37 °C (110°F)
very low scald risk
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
DANGER
INSTALLATION REQUIREMENTS
●●
Installation conditions may affect how the water heater is
serviced. Read all related information in the “Installation
Manual”.
●●
The Water Heaters must be installed according to all local
and state codes or, in the absence of local and state codes,
the most recent edition of the “National Fuel Gas Code
(ANSI Z223.1/NFPA 54)” in the USA or the “National Gas and
Propane Installation Code (CAN/CSA B 149.1)” in Canada.
●●
Massachusetts code requires this water heater to be installed
in accordance with Massachusetts Plumbing and Fuel Gas
Code 248 CMR Section 2.00 and 5.00.
Version 2.21
WARNING
WARNING
GAS TYPE and AC VOLTAGE
This water heater is configured for Natural Gas from the factory.
If conversion to Propane Gas is required, the conversion kit
supplied with the water heater must be used.
●●
Be sure to use 120 VAC, 60 Hz, minimum 2 A current. Using
abnormally high or low AC voltage may cause abnormal
operation, and may reduce the life expectancy of this
product.
If the unit does not match requirements, do not service,
please contact Navien immediately.
●●
WARNING
GAS CONVERSION
The conversion kit shall be installed by a qualified service
agency* in accordance with Navien’s instructions and all
applicable codes and requirements of the authority having
jurisdiction. The information in these instructions must be
followed to minimize the risk of fire or explosion or to prevent
property damage, personal injury or death. The qualified
service agency is responsible for the proper installation of
this kit. The installation is not proper and complete until the
operation of the converted appliance is checked as specified in
the manufacturer’s instructions supplied with the kit.
* A qualified service agency is any individual, firm, corporation
or company which either in person or through a representative
is engaged in and is responsible for the connection, utilization,
repair or servicing of gas utilization equipment or accessories;
who is experienced in such work, familiar with all precautions
required, and has complied with all of the requirements of the
authority having jurisdiction.
●●
●●
●●
●●
●●
In Canada: The conversion shall be carried out in accordance
with the requirements of the provincial authorities having
jurisdiction and in accordance with the requirements of the
CAN‐B149.1 and CAN1‐B149.2 Installation Code.
Navien, Inc. is not liable for any property damage and/or
personal injury resulting from unauthorized conversions.
●●
Shut off the gas supply if the water heater is damaged.
Have your installer or plumber show you the location of the
gas shut off valve and demonstrate how to close the valve. If
the water heater is damaged as a result of overheating, fire,
flood, or any other reason, close the manual shut off valve
and do not operate the water heater again until it has been
inspected by a qualified technician.
Do not store or use gasoline or other flammable liquids
near this water heater.
Doing so may result in fire or explosion.
Do not place combustibles, such as newspapers or
laundry, near the water heater or venting system.
Doing so may result in a fire.
Do not place or use hair sprays, spray paints, or any other
compressed gases near the water heater or venting
system, including the vent termination.
Doing so may result in fire or explosion.
Do not operate the water heater with the front cover
opened.
Doing so may result in fire or carbon monoxide (CO)
poisoning, which may result in property damage, personal
injury, or death.
Do not operate this water heater without proper venting.
Doing so may result in fire or carbon monoxide (CO)
poisoning, which may result in property damage, personal
injury, or death. Inspect the vent termination and air intake
supply annually to ensure proper operation of the water
heater. Turn off and discontinue use of the water heater
if any of the vent pipes, vent elbows, or intake pipes are
damaged in any way, separated at a joint, or show evidence
of corrosion, rusting, or melting.
Do not touch the power cord or internal components of
the water heater with wet hands.
Doing so may result in electric shock.
Safety Information
Downloaded from www.Manualslib.com manuals search engine
11
2. Product Information
CAUTION
●●
●●
●●
●●
●●
●●
●●
●●
●●
●●
●●
●●
●●
●●
12
Do not attempt to repair or replace any part of the water
heater, unless it is specifically recommended in this
manual.
For all other service, contact an authorized technician or
licensed professional. Improper adjustments, alterations,
service, or maintenance may lead to property damage,
personal injury, or death and will void your warranty.
2.1 Product Information
Navien features the new NPE “A” Series tankless gas water heater
with a built-in Circulation Pump and Mini Buffer Tank (the NPE ”S”
series tankless gas water heater features a built-in Mixing Valve).
Depending on the heat capacity, each model is divided into four
types; 150,180,210 and 240.
NPE
Do not operate the water heater if you feel something is
wrong with it.
Doing so may result in product damage or personal injury.
Items
Do not allow children to operate or access the water
heater.
Doing so may result in product damage or personal injury.
Intended Use
Do not attempt to change the water temperature while
the water heater is being used.
Doing so may result in personal injury.
Do not turn on the water heater unless the water and gas
supplies are fully opened.
Doing so may damage the water heater.
Do not turn on the water if the cold water supply shutoff valve is closed.
Doing so may damage the water heater.
Do not use this water heater for anything other than its
intended purpose, as described in this manual.
Features
“A” Models
(NPE-180A/210A/240A)
“S” Models
(NPE-150S/180S/
210S/240S)
Residential, Commercial or Combi*
Built-in Circulation
Pump and Mini Buffer
Tank
Built-in Mixing Valve
Factory
Default
Temperature
120 °F (49 °C)
Gas Type
NG, field-convertible to LP
See “3.1 General Specifications” for detailed specifications.
* “Combi” refers to a combination potable water and space heating
application. These water heaters cannot be used in space heating-only
applications.
Do not remove the front cover unless the power to the
water heater is turned off or disconnected.
Failure to do so may result in electric shock.
When servicing the controls, label all wires prior to
disconnecting them.
Failure to do so may result in wiring errors, which can lead to
improper or dangerous operation.
Do not use unapproved replacement or accessory parts.
Doing so may result in improper or dangerous operation
and will void the manufacturer’s warranty.
Do not place anything in or around the vent terminals,
such as a clothes line, that could obstruct the air flow in
or out of the water heater.
This water heater has been approved for use in the USA
and Canada only.
Using the water heater in any other country will void the
manufacturer’s warranty.
Should overheating occur or the gas supply fail to shut
off, turn off the manual gas valve to the appliance.
Do not use this appliance if any part has been under
water.
Immediately call a qualifed service technician to inspect the
appliance and to replace any part of the control system and
any gas control which has been under water.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
2.2 Layout and Key Components
The following diagram shows the key components of the water heater. Component assembly diagrams and particular parts lists are included
in the Appendix.
Exhaust Duct
Exhaust Limit Temperature Sensor
Intake Air Duct
Exhaust Body
Fan Motor
Ignition Transformer
Burner
Dual Venturi
Primary Heat Exchanger
High Limit Switch
Gas Pipe
Secondary Heat Exchanger
APS (Air Pressure Sensor)
Flow Sensor
Buffer Tank
Front Panel
Circulation Pump
Condensate Trap
Gas Valve
PCB Box
Water Adjustment Valve
2-Way Valve
Gas Inlet Fitting
Water Inlet Filter
Power Switch
DHW Supply Fitting
Condensate Drain Fitting
Recirculation Inlet Fitting
Condensate Drain Lid
[NPE-180A/ 210A/ 240A]
* Refer to components Diagram and Part List in page 133.
Product Information
Downloaded from www.Manualslib.com manuals search engine
13
Exhaust Duct
Exhaust Limit Temperature Sensor
Intake Air Duct
Exhaust Body
Fan Motor
Ignition Transformer
Burner
Dual Venturi
Primary Heat Exchanger
High Limit Switch
Gas Pipe
APS (Air Pressure Sensor)
Secondary Heat Exchanger
Freeze Protection Switch
Front Panel
Condensate Trap
Gas Valve
PCB Box
Flow Sensor
Water Adjustment Valve
Mixing Valve
Gas Inlet Fitting
Water Inlet Filter
Power Switch
DHW Supply Fitting
Condensate Drain Fitting
Condensate Drain Lid
[NPE-180S/ 210S/ 240S]
* Refer to components Diagram and Part List in page 133.
14
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Exhaust Duct
Exhaust Limit Temperature Sensor
Intake Air Duct
Exhaust Body
Fan Motor
Ignition Transformer
Burner
Single Venturi
Primary Heat Exchanger
Gas Pipe
Secondary Heat Exchanger
Freeze Protection Switch
Front Panel
APS (Air Pressure Sensor)
Condensate Trap
PCB Box
Gas Valve
Flow Sensor
Water Adjustment Valve
Mixing Valve
Gas Inlet Fitting
Water Inlet Filter
DHW Supply Fitting
Condensate Drain Fitting
Condensate Drain Lid
[NPE-150S]
Product Information
Downloaded from www.Manualslib.com manuals search engine
15
3. Technical Data
3.1 General Specifications
The following table lists the specifications for the water heater. Additional specifications about water, gas, electric, and air supplies (venting)
appear in the Installation section.
Item
NPE-150S
Heat
Capacity
(Input)
Propane Gas
Energy
Factor
UEF (for NG & LP)
EF (Canada) (for NG & LP)
18,00015,000-150,000 BTU/H
120,000
15,000-150,000 BTU/H
BTU/H
0.96
0.96
0.97
0.97
0.97
0.99
6.8 GPM
8.4 GPM (32 L/m)
(25.8 L/m)
5.3 GPM
6.5 GPM (25 L/m)
(20 L/m)
3.2 GPM
4.3 GPM
4.2 GPM
(12 L/m)
(16 L/m)
(16 L/m)
17.3 in (W) x 27.4 in (H) x 13.2 in (D)
62 lbs
75 lbs
67 lbs
(28 kg)
(34 kg)
(30 kg)
Indoor or Outdoor Wall-Hung
Forced Draft Direct Vent
Electronic Ignition
15-150 PSI
Natural Gas
35 °F (19 °C) Temp Rise
Flow Rate
(DHW)
45 °F (25 °C) Temp Rise
67 °F (36 °C) Temp Rise
Dimensions
Weight
Installation Type
Venting Type
Ignition
Water Pressure
Natural Gas Supply Pressure
(from source)
Propane Gas Supply Pressure
(from source)
Natural Gas Manifold Pressure
(min-max)
Propane Gas Manifold Pressure
(min-max)
Minimum Flow Rate
Cold Water Inlet
Connection
Hot Water Outlet
Sizes
Gas Inlet
Main Supply
Power
Maximum Power
Supply
Consumption
Casing
Materials
Heat Exchangers
Venting
Safety
Devices
16
NPE-180(A)
NPE-180S
NPE-210(A)
NPE-210S
NPE-240(A)
NPE-240S
19,900-180,000 BTU/H
19,900-199,900 BTU/H
19,900-180,000 BTU/H
19,900-199,900 BTU/H
0.96
0.97
0.96
0.97
0.97
0.99
0.97
0.99
10.1 GPM (38 L/m)
11.2 GPM (42 L/m)
7.8 GPM (30 L/m)
8.7 GPM (33 L/m)
5.0 GPM
(19 L/m)
5.2 GPM
(20 L/m)
5.6 GPM
(21 L/m)
5.7 GPM
(22 L/m)
82 lbs
(37 kg)
75 lbs
(34 kg)
82 lbs
(37 kg)
75 lbs
(34 kg)
3.5 in WC-10.5 in WC
8 in WC-13in WC
-0.04 in WC -0.04 in WC - -0.84 in WC
-0.05 in WC - -0.36 in WC
-0.40 in WC
-0.05 in WC -0.05 in WC - -0.50 in WC
-0.10 in WC - -0.66 in WC
-0.42 in WC
0 GPM (0 L/m) for “A” models / 0.5 GPM (1.9 L/m) for “S” models
3
/4 in NPT
3
/4 in NPT
3
/4 in NPT
120 V AC, 60 Hz
-0.05 in WC - -0.58 in WC
-0.10 in WC - -0.78 in WC
200 W (max 2 A), 350 W (max 4 A) with external pump connected
Cold Rolled Carbon Steel
Primary Heat Exchanger: Stainless Steel
Secondary Heat Exchanger: Stainless Steel
2 in or 3 in PVC, CPVC, Polypropylene
Exhaust
2 in or 3 in Special Gas Vent Type BH (Class II, A/B/C)
2 in or 3 in PVC, CPVC, Polypropylene
Intake
2 in or 3 in Special Gas Vent Type BH (Class II, A/B/C)
Vent Clearances
0 in to combustibles
Flame Rod, APS, Ignition Operation Detector, Water Temperature High Limit Switch, Exhaust Temperature High Limit Sensor,
Power Surge Fuse
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
3.2 Dimensions
27.4" (695mm)
Supply Connections
A
Air Intake
2"
B
Exhaust Gas Vent
2"
C
Hot Water Outlet
3/4"
D
Recirculation Inlet
(“A” models only)
3/4"
E
Cold Water Inlet
3/4"
F
Gas Inlet
3/4"
G
Condensate Outlet
1/2"
Supply Connections
A
1.5" (38mm)
Diameter
C
B
F
D
G
E
14.3" (364mm)
2.6" (67mm)
3.0" (77mm) 0.4" (10mm)
Overhead View
Description
6.7" (170mm)
2.4" (61mm)
2.4" (61mm)
4.5" (115mm)
13.2" (336mm)
28.8" (731mm)
The following diagrams show the dimensions of the water heater and the table lists the supply connections.
2.3"
3.0"
(60mm) (77mm)
8.3"
(212mm)
17.3" (440mm)
Technical Data
Downloaded from www.Manualslib.com manuals search engine
17
4. System Details
4.1 Schematic and Flow Diagram
Primary Heat Exchanger
Buffer
Tank
Secondary Heat Exchanger
2-Way
Valve
Circulation
Pump
Open
2-way valve open for Internal Recirculation Mode
Flow
Sensor
Check
Valve
Water
Adjustment
Valve
Hot Water
Supply
Domestic Water
Supply
Internal Recirculation Mode
Primary Heat Exchanger
Buffer
Tank
Secondary Heat Exchanger
2-Way
Valve
2-way valve closed for External Recirculation Mode
Circulation
Pump
Water
Adjustment
Valve
Closed
Hot Water
Supply
Flow
Sensor
Check
Valve
Recirculation
Water Supply
Domestic
Water Supply
External Recirculation Mode
[NPE-180A/ 210A /240A]
18
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Primary Heat Exchanger
Secondary Heat Exchanger
Flow
Adjustment
Valve
Hot
Water
Supply
Mixing
Valve
Flow
Sensor
Cold
Water
Supply
[NPE-150S/ 180S / 210S / 240S]
System Details
Downloaded from www.Manualslib.com manuals search engine
19
4.2 Operation Flow Chart
120v Power
Applied
IG : Igniter
MGV1 : Main Gas valve 1
MGV2 : Main Gas valve 2
System
Initialization
Displays version
NO
Standby Mode
Flow sensor
≥ 0.53 gpm
Yes
Yes
Fan start-up &
Fan control
IG ON
MGV1 ON
MGV2 ON
NO
Stage 2
Stage 1 or
Stage 2 ?
Stage 1
Dual venturi OFF
NO
Flame ON?
Dual venturi ON
Flame check time
> 3 sec
Yes
IG OFF
Burner Operation
NO
Flow sensor
≤ 0.48 gpm
Yes
MGV1 OFF
MGV2 OFF
Post Purge
Fan Stop
20
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
1. Water Flow Begins
●● Water Flow Sensor sends pulses to the PCB when it registers
water flow.
●● PCB senses flow greater than 0.53 GPM (approximate).
●● Firing Sequence begins.
2. Firing Sequence
●● PCB monitors Inlet / Outlet water temperature, temperature
set point, and water flow rate.
●● Fan Motor activates Purge Cycle in the combustion chamber.
●● Spark igniter begins ignition process.
●● Main Gas control valve opens to minimum fire rate.
●● Flame rod ignition confirms ignition and initial combustion.
●● Spark igniter stops ignition process.
4.3 Setting the DIP Switches
The water heater has two DIP switch locations: on the main circuit
board (PCB) and on the front panel. Each location has two sets
of DIP switches that control the functionality of the water heater.
Set the DIP switches appropriately, based on the installation
environment and the gas type.
4.3.1 Setting the DIP Switches
The water heater has two DIP switch locations: on the main circuit
board (PCB) and on the front panel. Each location has two sets
of DIP switches that control the functionality of the water heater.
Set the DIP switches appropriately, based on the installation
environment.
Circuit Board DIP Switches
3. Normal Operation
●● PCB monitors flame rod, fan motor frequency, outlet water
temperature, PCB temperature set point and water flow rate.
●● Main Gas control valve modulates gas input to required
firing rate.
●● Combustion fan speed is adjusted for the required firing rate.
●● Water adjustment valve is adjusted as needed.
4. Shut-down Sequence
●● PCB senses flow rate less than 0.48 GPM (approximate).
●● Main Gas Control valve closes.
●● Water adjustment valve resets to standby position.
●● Fan Motor activates Purge Cycle in the combustion chamber
at low speed.
The two sets of DIP switches on the circuit board configure the
water heater’s model settings. These configurations are set at the
factory and should not be changed.
Setting the Front Panel DIP Switches
The two sets of DIP switches on the front panel configure the water
heater’s pump & recirculation, display, well pump, storage tank &
solar system, lime alarm, high altitude, Cascade Venting and Gas
Type settings. Some of these configurations are set at the factory
and should not be changed. The following tables describe the
functions of the DIP switches and their settings:
5. Standby Mode
●● PCB monitors water temperature and remote controls.
●● Freeze protection is activated as needed.
ON
1
ON
2
3
4
5
6
7
8
9
10
System Details
Downloaded from www.Manualslib.com manuals search engine
21
●●
10-switch Panel:
Setting
Switch
Function
“A” models
(NPE-180A/ 210A / 240A)
“S” models
DIP switch setting
(NPE-150S/180S/210S/240S)
No Recirculation
Recirculation
Mode- Internal
Navien Pump
("A" models only)
1-3
5
6
7&8
Display
Temperature Unit
22
No Recirculation
1-ON; 2-OFF; 3-OFF
External Recirculation
No Recirculation
1-OFF; 2-ON; 3-OFF
Intelligent Preheating*
No Recirculation
1-ON; 2-ON; 3-OFF
1-OFF; 2-OFF; 3-ON
External Recirculation
External Pump Only
1-ON; 2-OFF; 3-ON
External Recirculation
External Pump Only
1-OFF; 2-ON; 3-ON
Intelligent Preheating*
Intelligent Preheating*
(External Pump Only)
1-ON; 2-ON; 3-ON
Celsius (with L/M)
4-ON
Fahrenheit (with GPM)
4-OFF
Well Pump Operation
5-ON
Do Not Use Well Pump
5-OFF
Storage Tank/Solar System Operation
6-ON
Do Not Use Storage Tank/Solar System
6-OFF
Off
7-OFF; 8-OFF
6 Months Alert
7-ON; 8-OFF
12 Months Alert
7-OFF; 8-ON
24 Months Alert
7-ON; 8-ON
0 ~ 1,999 ft (0 ~ 609 m)
9-OFF, 10-OFF
2,000 ~ 5,399 ft (610 ~ 1,645 m)
9-ON, 10-OFF
5,400 ~ 7,699 ft (1,646 ~ 2,346 m)
9-OFF, 10-ON
7,700 ~ 10,100 ft (2,347 ~ 3,078 m)
9-ON, 10-ON
Well Pump
DHW Storage
Tank/Solar
System
Lime Alarm***
High Altitude ****
9 & 10
Internal Recirculation
External Pump Only
Recirculation
ModeExternal Pump
Connected**
4
1-OFF; 2-OFF; 3-OFF
(Applies to Main
PCB version V1.4
(July 11, 2013) or
later versions only)
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Remark
*Intelligent Preheating:
Learns the user's hot water
usage patterns and starts
preheating prior to an
anticipated draw.
●● Preheating starts when
remote controller is not
connected.
●● When remote controller
is connected, preheating
starts and operates based
on the timer.
●● Set the timer on the
remote controller to use
hot water at the time of
your choice.
●● Intelligent preheating does
not function in Cascade
Mode (Preheating OFF).
●● Freeze protection is still
available with preheating
OFF.
●● When installing an NPE
water heater with NR,
NP or CH series units
for a cascade system,
temperatures are displayed
in Fahrenheit only.
●● For NPE“S” models,
preheating is not available
when using a cascade
configuration.
**External Pump:
These settings are to be used
when an external pump is
wired to the water heater.
***Lime Alarm:
Displays a "760" error when
the set time period has been
reached to indicate a flush or
service is necessary.
****High Altitude
Above 2,000 ft (610 m), the
water heater will de-rate by
4% for each 1,000 ft (305 m)
of altitude gain.
Version 2.21
NOTE
●●
●●
To use the water heater at a specific altitude, the DIP switches should be set as described above.
●●
When configuring a cascade system, all settings other than the high altitude, gas type and preheating settings are controlled by the DIP
switch settings on the master unit.
●●
When installing an NPE water heater with NR, NP, or CH series units, individual unit settings apply to the lime alarm and cascade venting.
2-switch Panel:
Switch
Function
1
Cascade Vent
2
Setting
Common Vent
1-OFF
Individual Vent
1-ON
Gas Type
Natural Gas
OFF
(Applies to Main PCB & Front panel
version V1.4 (July 11, 2013) or later
versions only.)
Propane Gas
ON
System Details
Downloaded from www.Manualslib.com manuals search engine
23
4.4 Measuring the Inlet Gas Pressure
4. Remove the water heater front cover by loosening the
4 Phillips head screws securing it to the case.
WARNING
The water heater cannot function properly without sufficient
inlet gas pressure. Measuring the inlet gas pressure should be
performed by a licensed professional only.
●●
●●
The inlet gas pressure must be maintained between 3.5” and
10.5” WC for natural gas and between 8.0” and 13” WC for
liquefied propane.
The appliance and its individual shutoff valve must be
disconnected from the gas supply piping system during any
pressure testing of that system at test pressures in excess of
1/2 psi (3.5 kPa). The appliance must be isolated from the gas
supply piping system by closing its individual manual shutoff
valve during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 psi (3.5 kPa).
5. Loosen the screw indicated in the figure below and connect a
manometer to the pressure port. Reset the manometer to zero
before use.
To measure the inlet gas pressure:
1. Shut off the manual gas valve on the gas supply line.
Digital pressure
manometer
Gas Valve
Opened
Closed
2. Open a hot water faucet. The water heater should turn on and
the gas in the gas supply line will be purged.
6. Re-open the manual gas valve and check for leaks.
7. Open multiple fixtures that have high flow rates, such as
bathtub and shower faucets, to ramp the water heater up to its
maximum firing rate.
8. When the water heater reaches its maximum firing rate, check
the inlet gas pressure reading on the manometer. The gas
pressure must fall within the proper operating range indicated
above and in the specifications on page 25.
3. Leave the faucet on until the water heater shuts down due to a
lack of gas supply, and then turn off the hot water faucet.
24
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.4.1 Gas Pipe Sizing Tables (Referenced from 2012 National Fuel Gas Code)
These tables are for reference only. Please consult the gas pipe manufacturer for actual pipe capacities.
Maximum Natural Gas Delivery Capacity
in Cubic Feet (ft3) per Hour (0.60 Specific Gravity; 0.5” WC Pressure Drop). Contact your gas supplier for BTU/ft3 ratings. Use 1,000 BTU/ft3 for
simplified calculations. This table is recommended for supply pressures less than 6” WC.
Length (including fittings)
Pipe Size
10'
(3m)
20'
(6m)
30'
(9m)
40'
(12m)
50'
(15m)
60'
(18m)
70'
(21m)
80'
(24m)
90'
(27m)
100'
(30m)
125'
(38m)
3/4"
360
247
199
170
151
137
126
117
110
104
92
1"
678
466
374
320
284
257
237
220
207
195
173
1 1/4"
1,390
957
768
657
583
528
486
452
424
400
355
1 1/2"
2,090
1,430
1,150
985
873
791
728
677
635
600
532
2"
4,020
2,760
2,220
1,900
1,680
1,520
1,400
1,300
1,220
1,160
1,020
2 1/2"
6,400
4,400
3,530
3,020
2,680
2,430
2,230
2,080
1,950
1,840
1,630
3"
11,300
7,780
6,250
5,350
4,740
4,290
3,950
3,670
3,450
3,260
2,890
4"
23,100
15,900
12,700
10,900
9,660
8,760
8,050
7,490
7,030
6,640
5,890
in Cubic Feet (ft3) per Hour (0.60 Specific Gravity; 3.0” WC Pressure Drop). Contact your gas supplier for BTU/ft3 ratings. Use 1,000 BTU/ft3 for
simplified calculations. This table is recommended for supply pressures of 6” WC or greater.
Length (including fittings)
Pipe Size
10'
(3m)
20'
(6m)
30'
(9m)
40'
(12m)
50'
(15m)
60'
(18m)
70'
(21m)
80'
(24m)
90'
(27m)
100'
(30m)
125'
(38m)
1/2"
454
312
250
214
190
172
158
147
138
131
116
3/4"
949
652
524
448
397
360
331
308
289
273
242
1"
1,787
1,228
986
844
748
678
624
580
544
514
456
1 1/4"
3,669
2,522
2,025
1,733
1,536
1,392
1,280
1,191
1,118
1,056
936
1 1/2"
5,497
3,778
3,034
2,597
2,302
2,085
1,919
1,785
1,675
1,582
1,402
2"
10,588
7,277
5,844
5,001
4,433
4,016
3,695
3,437
3,225
3,046
2,700
2 1/2"
16,875
11,598
9,314
7,971
7,065
6,401
5,889
5,479
5,140
4,856
4,303
3"
29,832
20,503
16,465
14,092
12,489
11,316
10,411
9,685
9,087
8,584
7,608
4"
43,678
30,020
24,107
20,632
18,286
16,569
15,243
14,181
13,305
12,568
11,139
System Details
Downloaded from www.Manualslib.com manuals search engine
25
Maximum Liquefied Propane Delivery Capacity
in Thousands of BTU/H (0.5” WC Pressure Drop)
Length (including fittings)
Pipe Size
10'
(3m)
20'
(6m)
30'
(9m)
40'
(12m)
50'
(15m)
60'
(18m)
80'
(24m)
100'
(30m)
125'
(38m)
150'
(45m)
175'
(53m)
200'
(60m)
250'
(76m)
1/2"
291
200
160
137
122
110
101
94
89
84
74
67
62
3/4"
608
418
336
287
255
231
212
197
185
175
155
140
129
1"
1,150
787
632
541
480
434
400
372
349
330
292
265
243
1 1/4"
2,350
1,620
1,300
1,110
985
892
821
763
716
677
600
543
500
1 1/2"
3,520
2,420
1,940
1,660
1,480
1,340
1,230
1,140
1,070
1,010
899
814
749
2"
6,790
4,660
3,750
3,210
2,840
2,570
2,370
2,200
2,070
1,950
1,730
1,570
1,440
NOTE
26
●●
For installations using CSST (flexible) gas piping, please refer to the sizing charts provided by the manufacturer.
●●
The use of single-stage regulators are recommended. Dual-stage regulators could cause operational issues with the water heater.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.5 Selecting a Recirculation Mode
3. Set the front panel DIP switches at the far left (set of ten) to:
1—ON; 2—OFF.
On all “A“ model Navien water heaters, you can choose from
two pre-heating modes: internal recirculation mode or external
recirculation mode. To select a recirculation mode, you must set
the DIP switches on the front panel, and set the position of the
2-way valve inside the water heater. By default, the DIP switches
are set to OFF.
When you use a recirculation mode, there will be some minor
efficiency loss as a result of the water heater maintaining a steady
temperature within the circulation loop. Although in many cases,
higher gas usage will be made up for by lower water usage.
The recirculation feature of the “A“ models has three performance
advantages:
●●
●●
●●
Elimination of any minimum flow rate requirement.
Elimination of any hot/cold/hot stacking—the “cold water
sandwich“ effect.
Quicker hot water delivery to fixtures, which results in less water
wasted.
ON
1
ON
2
3
4
5
6
7
8
9
10
NOTE
When using external recirculation mode with the built-in
pump, observe the following maximum recirculation pipe
lengths including fittings (3/4” pipe is recommended):
-1/2” Copper Pipe- 100’ (30m) of equivalent length
-3/4” Copper Pipe- 500’ (150m) of equivalent length
Lengths in excess of these limits will require a properly sized
external recirculation pump.
Internal Recirculation Mode
To use the internal recirculation mode:
The following diagram shows the internal recirculation flow for
pre-heating:
Primary Heat Exchanger
Buffer
Tank
Secondary Heat Exchanger
1. Connect the water supply. Refer to the “Installation Manual
(page 19)”.
2. Set the 2-way valve inside the water heater to “INT.“
2-Way
Valve
Open
Circulation
Pump
Flow
Sensor
Check
Valve
Water
Adjustment
Valve
Hot Water
Supply
Domestic Water
Supply
Internal Recirculation Mode
System Details
Downloaded from www.Manualslib.com manuals search engine
27
External Recirculation Mode
The following diagram shows the external recirculation flow for
pre-heating:
To use the external recirculation mode:
1. Connect the water supply to support recirculation. Refer to the
“Installation Manual (page 20)”.
Primary Heat Exchanger
2. Set the 2-way valve inside the water heater to “EXT.“
Buffer
Tank
Secondary Heat Exchanger
2-Way
Valve
Circulation
Pump
Water
Adjustment
Valve
Closed
3. Set the front panel DIP switches at the far left (set of ten) to:
1—OFF; 2—ON.
Hot
Water
Supply
Flow
Sensor
Check
Valve
Recirculation
Water Supply
Domestic
Water
Supply
External Recirculation Mode
ON
1
28
ON
2
3
4
5
6
7
8
9
10
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.6 Gas Conversion
NPE Series water heaters are configured for Natural Gas from the
factory. If conversion to Propane Gas is required, the conversion kit
supplied with the water heater must be used.
Water
Heater
NG
LP
NPE-150S
Ø6.30
Ø5.10
Procedure:
WARNING
This conversion kit shall be installed by a qualified service
agency* in accordance with Navien’s instructions and all
applicable codes and requirements of the authority having
jurisdiction. The information in these instructions must be
followed to minimize the risk of fire or explosion or to prevent
property damage, personal injury or death. The qualified
service agency is responsible for the proper installation of
this kit. The installation is not proper and complete until the
operation of the converted appliance is checked as specified in
the manufacturer’s instructions supplied with the kit.
1. Turn off both gas and water supply to the water heater.
2. Using a Phillips hand screwdriver, remove 4 screws (2 from the
top and 2 from the bottom) of the front cover assembly to gain
access to the internal components. See Figure 1 for illustration
of the front cover on the unit.
* A qualified service agency is any individual, firm, corporation or company
which either in person or through a representative is engaged in and
is responsible for the connection, utilization, repair or servicing of gas
utilization equipment or accessories; who is experienced in such work,
familiar with all precautions required, and has complied with all of the
requirements of the authority having jurisdiction.
In Canada: The conversion shall be carried out in accordance with
the requirements of the provincial authorities having jurisdiction
and in accordance with the requirements of the CAN-B149.1 and
CAN1-B149.2 Installation Code.
Tools Required:
●●
●●
●●
●●
●●
Figure 1. NPE Series Front cover
Phillips Screwdriver
Flathead Screwdriver
5/32” or 4mm Allen Wrench
Combustion Analyzer or Dual Port Manometer
Gas Leak Detector
Included Items:
●●
Water
Heater
●●
Gas Inlet
Pipe
Gas Orifice (refer to below table)
NG
LP
1STAGE
2STAGE
1STAGE
2STAGE
NPE-180A
NPE-180S
Ø4.80
Ø5.95
Ø3.80
Ø4.70
NPE-210A
NPE-210S
Ø6.10
Ø6.30
Ø4.50
Ø4.80
NPE-240A
NPE-240S
Ø6.10
Ø6.30
Ø4.50
Ø4.80
Gas Valve
Figure 2. NPE Series Internal Components
Table 1. Orifice size
Gas Pressure and Conversion Kit Number Labels
System Details
Downloaded from www.Manualslib.com manuals search engine
29
3. Once the front cover is removed, place it in a safe location to
prevent accidental damage. With the internal components
exposed, locate the gas inlet pipe and the Gas Valve near the
left side of the unit which are highlighted in Figure 2.
4. Use a Phillips screwdriver to remove the two screws at Location
A - the connection below the Gas Valve where it connects
to the pipe. See Figure 3 for reference. Once the screws are
removed, carefully separate the pipe from the Gas Valve.
5. Once the gas inlet pipe is detached from the Gas Valve, find
Location B - the connection above the Gas Valve where it is
attached to the Fan Motor Assembly. Carefully remove the four
screws by hand using a Phillips screwdriver and pull the Gas
Valve away from the Fan Assembly to access the Gas Orifice.
6. Once the Gas Orifice is exposed, remove the two screws that
hold the part in place. Remove the Gas Orifice from its housing
and prepare the new Gas Orifice for the LP conversion for
installation.
Remove two (2)
screws here
Location B:
Remove four
(4) screws here
Figure 4. Access to Gas Orifice in Fan Assembly
Location A:
Remove two (2)
screws here
Figure 3. Detaching Gas Valve from
Gas Inlet Pipe and Fan Motor Assembly
30
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
WARNING
●●
DO NOT adjust or attempt to measure gas valve outlet
pressure. The gas valve is factory-set for the correct outlet
pressure. This setting is suitable for natural gas and propane,
requiring no field adjustment.
●●
Attempting to alter or measure the gas valve outlet pressure
could result in damage to the valve, causing potential severe
personal injury, death or substantial property damage.
Navien water heaters are shipped ready to fire natural gas
ONLY.
Version 2.21
DANGER
Gas Orifice
See Figure 5. Inspect the O-ring between the gas valve and
gas valve inlet adapter whenever they are disassembled.
The O-ring must be in good condition and must be installed.
Failure to comply will cause a gas leak, resulting in severe
personal injury or death.
O-ring
LP
NPE-150S
NG
NPE-180A/ 210A/ 240A/ 180S/ 210S/ 240S
Figure 6. Orifice identification
7. Replace the old Orifice piece with the new part for use with LP
gas. Ensure that the Orifice is properly seated inside the port
before proceeding to the next step.
<NPE-150S>
8. Replace the gas inlet pipe to its original position and use all
screws to secure all connections.
Note
Do not overtighten as this may damage or crack
the components.
DANGER
Gas Orifice
Inspect the O-ring between the gas valve and gas valve inlet
adapter whenever they are disassembled. The O-ring must be
in good condition and must be installed. Failure to comply will
cause a gas leak, resulting in severe personal injury or death.
O-ring
9. Set the Front Panel Dip switch according to the gas type.
WARNING
Be sure to turn off the power before changing the DIP switch
setting.
<NPE-180A/ 210A/ 240A/ 180S/ 210S/ 240S>
Figure 5. Exploded view of Gas assembly
System Details
Downloaded from www.Manualslib.com manuals search engine
31
ON
1
ON
2
3
4
5
6
7
8
9
NG
10
1
2
LP
1
2
1
2
DANGER
●●
●●
High fire
Low fire
%CO2
%CO2
NG
8.9
9.5
LP
10.2
10.8
NPE-180A
NPE-180S
NG
8.9
9.5
LP
10.2
10.8
NPE-210A
NPE-210S
NG
8.9
9.5
LP
10.2
10.8
NPE-240A
NPE-240S
NG
8.9
9.5
LP
10.2
10.8
Water
Heater
When conversion is required, be sure to set the Front Panel
DIP switches according to the supply gas type.
Failure to properly set the DIP switches could cause carbon
monoxide poisoning, resulting in severe personal injury or
death.
10. Turn on the gas and water supply to the water heater.
11. Measure and adjust the gas/air ratio.
Option 1. Using Combustion Analyzer (recommended)
a. Loosen the screw, rotate the plate and remove the gasket
to access the emissions monitoring port as shown in
Figure 7.
b. Insert the analyzer into the port (Figure 7).
NPE-150S
Fuel
Table 2. CO2 and CO value
(CO2 values must be within 0.5% of the values listed.)
c. Fully open several hot water fixtures and set the
water heater to operate at 1-stage MIN mode (refer to
page 40). Measure the CO2 value at low fire.
If the CO2 value is not within 0.5% of the value listed in
Table 2, the gas valve set screw will need to be adjusted.
If adjustment is necessary, locate the set screw as shown
in Figure 8. Using a 5/32 in or 4 mm Allen wrench, turn
the set screw no more than 1/4 turn clockwise to raise or
counterclockwise to lower the CO2 value.
Figure 8. Set Screw Location
Figure 7
32
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Note
The set screw is located behind the screw-on
cover. This must be removed first.
Version 2.21
d. Fully open several hot water fixtures and set the water
heater to operate at 2-stage MAX mode (refer to
page 40). Measure the CO2 value at high fire.
If the CO2 values do not match Table 2 at high fire, do not
adjust the gas valve. Check for the proper Gas Orifice.
DANGER
Improper gas valve settings can cause severe personal injury,
death or substantial property damage.
c. Fully open a hot water fixture and set the water heater to
operate at 1-stage MIN mode (refer to page 40). Measure
the offset value at low fire and compare it to the values in
Table 3. If the offset value is out of range, the gas valve set
screw will need to be adjusted.
If adjustment is necessary, locate the set screw as shown
in Figure 10. Using a 5/32 in or 4 mm Allen wrench, turn
the set screw no more than 1/4 turn clockwise to raise or
counterclockwise to lower the offset value.
Option 2. Using Digital Manometer
a. Open the offset pressure port by loosening the screw two
turns as shown in Figure 9.
Figure 10
Note
d. At high fire, do not check the offset value and never adjust
the gas valve.
Figure 9
b. Connect a manometer to the offset pressure port. For dual
port manometers, use the positive pressure side.
Model
NPE-150S
NPE-180A
NPE-180S
NPE-210A
NPE-210S
NPE-240A
NPE-240S
The set screw is located behind the screw-on
cover. This must be removed first.
Kit Part No.
Gas Type
Offset
NAC-N6
LP
-0.03 in ± 0.01 in
NAC-L6
NG
-0.04 in ± 0.01 in
NAC-01
LP
-0.03 in ± 0.01 in
NAC-100
NG
-0.04 in ± 0.01 in
NAC-02
LP
-0.02 in ± 0.01 in
NAC-200
NG
-0.04 in ± 0.01 in
NAC-03
LP
-0.02 in ± 0.01 in
NAC-300
NG
-0.04 in ± 0.01 in
Table 3. Offset value for low fire
DANGER
Improper gas valve settings can cause severe personal injury,
death or substantial property damage.
12. Once the CO2 or offset values have been confirmed, apply the
included conversion stickers to show that the appliance has
been converted to propane gas. Place this labels adjacent to
the rating plate as shown in Figure 11.
This unit has been
converted to Propane fuel
Cet appareil a ete converti au Propane
Orifice Size / Injecteur:
Min. 4.5 mm to Max. 4.8 mm
Inlet Gas Pressure / Pression d'entrée du gaz:
Min. 8.0 to Max. 13.0 inches
Manifold Gas Pressure /
Pression à la tubulure d’alimentation:
Min. -0.02 to Max. -0.66 inches WC
BTU Input / Debit calorifique:
Max. 180,000 - Min. 19,900 BTUh
Conversion Kit No.: NAC-02
This water heater was converted on
______/______/______ to ____________ gas
with Kit No. ________________________
by _________________________________
_________________________________
(name and address of organization making
this conversion, who accepts responsibility
for the correctness of this conversion)
Figure 11. Proper Placement of Gas Conversion Labels
System Details
Downloaded from www.Manualslib.com manuals search engine
33
4.7 The Front Panel
The front panel allows you to adjust the water temperature and
view the operating status or error codes. Remove the protective
sheet from the front panel before using it.
a
f
b
g
h
a
c
i
d
j
e
k
g
Error
A code will appear on the display
Master Unit
Cascade operation
b
Hot Water Recirculation
h
Display
Recirculation Mode
i
c
Diagnostics button
For installers only
Up button
Increases the temperature
j
d
Information button
Shows basic information
e
Down button
Decreases the temperature
k
Reset button
Resets the water heater (When an error occurs)
Power button
Turns the water heater on or off
f
Combusting
When the gas burner is on
34
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.7.1 Turning the Water Heater On or Off
4.7.2 Adjusting the Water Temperature
To turn the water heater on or off, press the Power button.
WARNING
Before adjusting the water temperature, read “HOT WATER
TEMPERATURE SETTING” on page 40 carefully. Water
temperatures above 120°F can cause instant scalding, severe
burns, or death.
The water heater is set to 120°F (49°C) by default. To adjust the
water temperature:
1. Make sure that all hot water faucets are closed, and ensure that
the internal circulator and any external circulating pumps are
off.
NOTE
When the power is on, the temperature will appear on the front
panel display.
If a hot water faucet is open, you can adjust the temperature
only from 98-110°F (37-43°C).
2. Press the + (Up) or – (Down) buttons until the desired
temperature appears on the display. You can adjust the
temperature while the display is flashing. Once the display
stops flashing, the temperature setting is stored.
NOTE
The water heater will retain your settings during a power
outage.
System Details
Downloaded from www.Manualslib.com manuals search engine
35
You can adjust the temperature by the below 10-degree
increments, depending on the temperature range:
Press the + or – buttons to switch between the information types.
Display
Description
Temperature range
Adjusting the water
temperature
98°F-120°F (Fahrenheit mode)
36°C-50°C (Celsius mode)
1°F or 0.5°C increments
Flow rate in gallons per minute
(GPM).
120°F-140°F (Fahrenheit mode)
50°C-60°C (Celsius mode)
Press the + or - buttons for
2 seconds to adjust in 5°F or
2°C increments
Hot water outlet temperature (OUT).
The water heater will not provide hot water instantly at the hot
water faucet unless a recirculation line has been installed from
the furthest fixture back to the water heater and the unit is set to
“external recirculation” mode.
Cold water inlet temperature (IN).
4.7.3 Using Commercial Mode
To use water above 140°F (60°C) (up to 182°F (83°C)), you can use
Commercial Mode.
●●
●●
To enter Commercial Mode: Press the up (+) and down (-) button
simultaneously for 10 seconds. “HIGH” appears on the display.
To exit Commercial Mode: Press the up (+) and down (-) button
simultaneously for 10 seconds. “LoW” appears on the display.
To exit information mode, press the Reset button.
4.7.5 Resetting the Water Heater
If an error message appears, you can try resetting the water heater
to resolve the problem. To reset the water heater, press the Reset
button.
NOTE
●●
To adjust the temperature, press the up (+) button for
5 seconds to adjust in 10°F (5°C) increments.
●●
Commercial Warranty Applies when this mode is used. Refer
to the Warranty for more details.
4.7.4 Viewing Basic Information
To view information about the water heater, press the Information
button.
If resetting the water heater does not solve the problem, refer to
the Troubleshooting section of this manual or contact Technical
Support at 1-800-519-8794.
36
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.7.6 LCD display
DISPLAY
Preheating icon
Error icon
Combustion icon
Master icon
Segment
Function description
Remark
Displays when a recirculation mode is activated.
When the remote controller is not connected: Preheating will operate based on the
setting of the DIP switches on the front panel.
When the remote controller is connected: Preheating will operate based on the
timer settings of the remote controller (recirculation mode must be selected on the
front panel)
When the AHU is connected: The preheating function of NPE will be turned off, and
the AHU heating icon will be displayed instead of the preheating icon.
Preheating setting
Displays an error icon when an error occurs.
When operation is maintained but an error is only displayed, the basic
operation(temperature setting, etc.) is normally possible. However, at this time, it is
impossible to adjust the setting temperature if hot water is in use.
Error situation
flashing
Error history off
Displays during a combustion cycle.
The combustion icon flashes at intervals of 1 second when the water heater is
operating to prevent freezing.
Displayed on the Master unit in a cascade system.
Master: ON, Slave: OFF
Flame signal state
display
On at Master
Displays data according to each setting and display condition on 4 segments.
IN
OUT
When displaying the cold water inlet temperature: IN displayed
When displaying the hot water outlet temperature: OUT displayed
L/M
The unit icon displays the current flow rate (in liters/min)
With display units set
to °C.
GPM
The unit icon displays the current flow rate (in gal/min)
With display units set
to °F.
%
Displayed in
information mode
The unit icon is displayed when indicating the percentage of a parameter.
Segment state display
Function
WAIT
Displayed while waiting for a response from the main controller when executing a
command
RST
Displayed during an alarm or error reset
CLR
Displayed when deleting the Error History or Tech Info
INIT
Displayed when initiating a Factory Reset
Remark
System Details
Downloaded from www.Manualslib.com manuals search engine
37
4.7.7 Button
Button
Description or
name
Diagnostic
Reset
Short Key
[Diagnostic] short key
Power
Information
Function
Display/confirmation of information for consumers
[RESET] short key
Error code release/reset
[PLUS] short key
Item movement/UP
Remark
Item movement/DOWN
Long Key combination
[POWER] long key(1 sec)
Minus
Display of information for service
[INFO] short key
[MINUS] short key
Plus
Function
Remark
Power ON/OFF
[INFO] long key(2 sec)
Error history display
Must be in Normal mode or Error
Display mode
[RESET] long key(5 sec)
Individual deletion of Error History /Tech Data
Works only at the relevant mode
[Diagnostic] long key(5 sec)
Advancement into Test Menu
Must be in Normal mode
[Diagnostic] long key(10 sec)
Version display
Power turned OFF
[PLUS] + [MINUS] long key (10 sec)
High temperature water setting/release(NPE-240A only)
Allows temperature settings
above 140°F (60°C)
[Diagnostic]+[PLUS] long key(5 sec)
Cascade: assigns master unit and completes set-up
Possible at Normal mode
[Diagnostic]+[MINUS] long
key(2 sec)
Cascade: assigns slave unit
[Diagnostic]+[RESET] long
key(5 sec)
Cancels cascade operation (from master unit) / removes
individual slave unit from cascade system
Possible at Normal mode with
Cascade operation activated
Cascade system power ALL ON/OFF
Possible only at Master, and
possible only with power turned
OFF or at a Normal Operation
condition
Factory reset
Possible only with power turned
OFF
[Diagnostic]+[POWER] long
key(5 sec)
[Diagnostic]+[PLUS]+[RESET]+[PO
WER] long key(5 sec)
* While buttons are being pressed on the front panel, the keypad will remain lit to its maximum brightness. After pressing a button, the keypad will dim to
medium brightness for 5 seconds, then dim to minimum brightness for 5-10 seconds and then completely turn OFF 10 seconds later.
* Button entries are recognized after pressing for a short period (50msec) and then releasing.
* If a button is pressed and held for a longer time as specified in the above chart, it will be recognized as a “long key” function.
38
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.7.8 Power ON/OFF
1. Turn the power ON/OFF by pressing the [POWER] button for
about 1 sec.
2. If the unit is experiencing an error, the error code will continue
to display on the front panel even if the unit is turned OFF.
Item
Description
Display method
Power ON: When the
setting temperature
is 120°F (Fahrenheit
specification)
Power ON
Power OFF
Normal operation
mode with power
turned ON
Power OFF
condition with
power turned OFF
Power ON: When the
setting temperature
is 60.0°C (Celsius
specification)
Power OFF: DISPLAY
ALL OFF except the
state icon (The state
icon is normally
displayed depending on
conditions)
6. When a level1 error occurs, the error icon flashes for 1 second
and the error code and the setting temperature are toggled
and displayed at intervals of 1 second (Level 1 Error = An error
that can be reset without turning the power OFF then ON).
7. Press the [Reset] button once for a level1 error so that “RST”
is displayed for 3 seconds and the error is released when the
error release condition is satisfied.
8. The water heater will function normally during an alarm or
level1 error.
Item
Description
Display method
When the setting temperature
is 120°F (Fahrenheit
specification)
Normal
condition
Normal
operation mode
with power
turned ON
Alarm
occurrence
When a lime
alarm period
set with a
dip switch is
reached
Level1 error
occurrence
When a level1
error occurs
* If power is initially applied, the panel is turned ON for 2 seconds. (To check
whether the LCD is defective)
When the setting temperature
is 60.0°C (Celsius specification)
1 sec flashing
4.7.9 Normal operation
1. Turn the water heater ON by pressing the [Power] button for
approximately 1 second.
2. The setting temperature will be displayed.
1 sec flashing
3. Under the usage of AHU & Outdoor sensor, when DHW is off
and space heating is on, the current heating temperature
based on the AHU outdoor temperature will be displayed, and
when space heating is off, DHW temperature setting will be
displayed.
4. When an alarm occurs, the “A.760” code and the setting
temperature are toggled and displayed at intervals of 1
second.
5. While an alarm occurs, press the [Reset] button for over
2 seconds to display “RST” and then release the alarm.
System Details
Downloaded from www.Manualslib.com manuals search engine
39
4.7.10 Setting the Operation Mode
4. The error code is displayed in 3 digits. (see below)
1. Using the Front Panel, press and hold the Diagnostics Button
for over 5 seconds until “1.TST” is displayed.
2. Press the + (Up) button once to change the display to “2.OPR”.
3. Press the Information Button once to acess the Operation
Mode menu.
4. Press the + (Up) button once to set the water heater to
opearate at 1-stage MIN (“MIN.1”).
5. To set the water heater to operate at 2-stage MAX, press the +
(Up) button 3 times or until “MAX.2” is displayed.
6. To exit the Operation Mode and return the water heater to
normal operation, press the Reset button twice.
5. While in the <error display mode>, it is possible to access
the User Info, Service Info, Error History and Component Test
mode.
6. Press the [RESET] button once with the error code displayed
to reset the water heater. The front panel will display “RST” for
3 seconds and then release the error if the cause of the error
has been resolved.
7. If it is impossible to release the error, the error code will display
after 3 seconds.
4.7.12 Hot water temperature setting
1. At the <Normal operation mode>, press the [+] or [-] button to
access the <hot water temperature control mode>.
Diagnostics
Information
Reset
2. If the <hot water temperature control mode> is displayed, the
temperature setting value flashes. → The temperature value is
displayed while the temperature is being set.
3. Adjust the temperature with the [+] / [-] button. (Operated
depending on the temperature range: See the following table
below).
4. Pressing the [+] / [-] button for over 2 seconds acts as a
continuous key and will rapidly adjust the temperature.
4.7.11 Error display and reset
1. Depending on the severity of the issue that is causing the
error, the water heater will either stop its operation or will only
be able to perform basic operations. A flashing red error icon
can be seen on the front panel along with the associated error
code.
2. When an error occurs while accessing other modes on the
front panel, press [RESET] to access the <error display mode>
while the error icon is flashing in order to view the error code.
3. While the panel is in the <error display mode>, the error icon
and code will flash in rotation at 1 second intervals.
40
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
5. It is impossible to increase the temperature above ~110°F
(43°C) while using the hot water(or only when at least 1 unit is
using hot water in a cascade system).
6. For high temperature applications, press the [+] + [-] button for
over 10 seconds to access temperature settings above 140°F
(60°C). (“HIGH” or “LOW” displayed for 2 seconds after setting)
7. Press the [Info] or [Reset] button once to return to the
<Normal operation mode>. (The temperature setting value is
maintained according to its last setting.)
8. If there is no button input for 5 seconds, then it automatically
returns to the <Normal operation mode>. (The temperature
setting value is is maintained according to its last setting.)
Version 2.21
US/Canada specification
Temperature range
Increase/ decrease
value
[+] key
[+] continuous key
operation
[-] key
[-] continuous key
operation
98~120°F (36~50°C)
1°F( 0.5°C)
Short key
Increased every
100msec
Short Key
Decreased every
100msec
120~140°F
(50~60°C)
5°F ( 2°C )
2sec Long Key
Not working
Short Key
Decreased every
100msec
140~182°F
(60~83°C)
10°F ( 5°C)
180°F (80°C)
<->
182 (83°C)
5sec Long Key
Not working
Short Key
Decreased every
100msec
4.7.13 Viewing Basic Information
1. At the <Normal operation mode>, press the [Info] button once to access the Information Data.
2. Whenever the [+] / [-] button is pressed, the Information Data item can be selected and displayed.
3. The data items being currently outputted are displayed by an LED ICON. (Flow rate-GPM/LPM, leaving water temperature-OUT, entering
water temperature-IN)
4. Press the [Reset] button once to return to the <Normal operation mode>.
5. If there is no button input for 5 minutes, it automatically returns to the <Normal operation mode>.
Item
Description
●●
Flow rate
●●
●●
●●
Display of the current flow rate
Minimum display unit: 0.2 Gal/min or
l/min
Gal/min or l/min
Display of the current outgoing water
temperature
Water temperature
●●
Display of the current incoming water
temperature
Display method
GPM flow rate display
ex )10.2GPM
OUT temperature display
ex) 120°F
IN temperature display
ex)120°F
System
Version
Details
2.21
Downloaded from www.Manualslib.com manuals search engine
41
4.7.14 Error occurrence history display
1. At the <Normal operation mode> or <Error display mode>, press the [Info] button for over 2 seconds to access the error history mode.
The most recent error will be displayed first.
2. When the [+] / [-] button is pressed, the error history can be searched. A total of 10 errors are stored in memory and are labeled from 0 to 9
with 0 being the most recent error.
3. Whenever the [Info] button is pressed, the previous error occurrence time difference(unit time, maximum 9999 hr) and the sub error code
are toggled and displayed.
4. Pressing the [Reset] button for 5 seconds while in the <ERROR HISTORY DISPLAY MODE> displays “CLR” and deletes all the ERROR HISTORY
DATA.
5. Press the [Reset] button once to return to the <Normal operation mode>.
6. If there is no button input for 5 minutes, then it automatically returns to the <Normal operation mode>.
While in <ERROR HISTORY DISPLAY MODE> the first digit indicates the history of the error with 0 being the most recent. The remaining 3
digits indicate the error code. If there is no error history, a “0” will be displayed.
Passed time display: The time between the currently displayed error and the just previously generated error is displayed in 1-hr unit.
(0 is displayed if the error code is empty)
Ex) When the most recent error code is 615, the sub error code is 5, and 24 hours have passed since the error was generated.
●●
When the Sub Error Code is 0(i.e., there is no sub error code), the display is as follows:
4.7.15 Service information display
1. At the <Normal operation mode>, press the [Diagnostic] button once to access the service information display.
2. Press [+] or[-] to navigate through the user parameters.
3. Item of current SERVICE Information Data is indicated as an alphabetical numbering on the first segment and relevant DATA value is
indicated at the 2nd, 3rd and 4th segment. (Alphabetical numbering A~Z are indicated and next ones and indicated as 1~9, then those
after that are indicated as symbols.)
4. Press the [Reset] button once to return to the <Normal operation mode>.
5. If there is no button input for 1 hour, then it automatically returns to the <Normal operation mode>.
6. The proper units are indicated with the LCD ICON for the applicable input items (Example: Water pressure - psi).
Item
(A)Flow rate
42
Description
Display of the current flow rate
Minimum display unit : 0.2
Gal/min or l/min
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Display method
GPM flow rate display
ex ) 10.2GPM
Version 2.21
Item
(B)Hot Water Outlet
temperature
(C)Water Inlet
temperature
Description
Display of the current outgoing water
temperature
Display of the current incoming water
temperature
Display method
OUT temperature display
ex) 120°F
IN temperature display
ex) 120°F
% Heat capacity display in percentage
ex) 92%
(D)Heat Capacity
(E)Water adjustment
valve condition
Display of current heat capacity %
Display of the water adjustment valve
condition(%)
Fully closed= 100%
Fully opened= 0%
% display of the valve close ratio in percentage
ex) When closed 24%
“A” models
(F)Mixing valve condition
(G)Heat exchanger flow
rate
Mixing valve condition display(%)
Fully closed= 0%
Fully opened= 56%
Calculated value by the mixing valve open
condition from the total flow rate
For “A” models, this flow will be the same
as (A)
“S” models: % display of the valve close ratio in percentage
ex) When closed 46%
GPM flow rate display
ex) Relevant flow rate: 5.4gpm
Display of RPM by omitting the last digit
ex) 3600rpm
(H)Current RPM
Fan motor RPM display
Display of the APS value as voltage up to the first decimal place
ex) 3.2V
(I) Current APS
APS voltage value display
System Details
Downloaded from www.Manualslib.com manuals search engine
43
Item
(J)Flame condition
Description
Flame detection current AD value display
Flame On: 8bit AD value less than 70
Flame Off: 8bit AD value more than 175
Display method
Display of the flame detection AD value
0~255
ex) 200
Exhaust gas temperature display
ex) 120°F
(K)Exhaust gas
temperature
Current exhaust gas temperature display
(L)Model and capacity
Currently set model and capacity display
The 2nd & 3rd digits represent the model
and the 4th digit represents the type of
unit.
ex) Capacity 180, Condensing
Preheating not working
Internal pump, internal circulation
Internal pump, external circulation
(M)Recirculation setting
information
* 2 nd letter: Pump
I: Internal Pump
E: External Pump
B: Both (Internal &
External) Pump
* 3 rd, 4th letters:
Circulation, Intelligent
Preheat
EC: External Circulation
IC: Internal Circulation
IT: Intelligent Preheat
Internal pump, intelligent preheating
Displays the recirculation mode that has
been selected on the front panel.
External pump, external circulation
Internal pump and external pump, internal circulation
Internal pump and external pump, external circulation
Internal pump and external pump, intelligent preheating
44
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Item
Description
Display method
CASCADE OFF
(N)Number of currently
working cascade units
Number of actually working units in the
current cascade system
CASCADE ON: Display of the number of working units
Ex) 8 units working
CASCADE OFF
CASCADE ON: MASTER UNIT, standby ON
CASCADE ON: MASTER UNIT, standby OFF
(O)Cascade information
Cascade ON/OFF condition display
Individual Master/Slave number and
operation condition display
Segment display: ID+o(ON)/X(OFF)
CASCADE ON: SLAVE UNIT, standby ON
ex) ID 12
CASCADE ON: SLAVE UNIT, standby OFF
ex) ID 12
NG
(P) Information on gas
type
Displays the current gas
<panel version : after v1.3>
LPG
System Details
Downloaded from www.Manualslib.com manuals search engine
45
Item
Description
Display method
0~2,000ft
2,000~5,400ft
(Q) Altitude setting
information
Displays the current altitude level setting
<panel version : after v1.5>
5,400~7,700ft
7,700~10,100ft
(R) Heat exchanger outlet
temperature
(S) Heat exchanger inlet
temperature
Display of the current outlet temperature
(Applies to Front panel version V1.6
(July 23, 2013) or later versions only)
Display of the current inlet temperature
(Applies to Front panel version V1.6
(July 23, 2013) or later versions only)
OUT temperature display
ex) 120°F
IN temperature display
ex) 120°F
AHU Off or AHU Outdoor Off
(T) AHU outdoor
temperature
Displays the current AHU outdoor
temperature.
AHU On & AHU Outdoor On
ex) 120°F
AHU Off or AHU Outdoor Off
(U) Heating temperature
based on the AHU
outdoor temperature
46
Displays the current heating temperature
based on the AHU outdoor temperature.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
AHU On & AHU Outdoor On
ex) 120°F
Version 2.21
4.7.16 Test information menu
1. At the <Normal operation mode>, press the [Diagnostic]
button for over 5 seconds to access the <TEST INFORMATION
MENU MODE>.
8. Press the [Reset] button once to return to the <TEST
INFORMATION MENU MODE>. (To the display of the previously
entered item 1.TST)
9. If there is no button input for 5 minutes, it automatically
returns to the <TEST INFORMATION MENU MODE>.
2. Select the desired test mode in the INFORMATION MENU using
the [+] / [-] button.
Item
Description
3. Press the [Info] button once to get into the currently displayed
item mode.
Fan Motor
Fan motor component
check menu display
Water
Adjustment
Valve
Water adjustment valve
component check
menu display
Dual Venturi
Dual Venturi
component check
menu display
4. Press the [Reset] button once to return to the <Normal
operation mode>.
5. If there is no button input for 5 minutes, then it automatically
returns to the <Normal operation mode>.
Display method
Display method
Item
Description
Component
check mode
Used to test the normal
operation of each
device
Pump
(“A” models
only)
Pump and flow sensor
component check
menu display
Operation
condition
setting mode
Used to test the
operation condition of
the water heater
Mixing valve
(“S” models
only)
Mixing valve
component check
menu display
Component
Test Performed
4.7.17 Component Check
1. While in <TEST INFORMATION MENU MODE>, press the [+] / [-]
button and then press the [Info] button once 1.TST is displayed
on the front panel.
2. After accessing <Component check mode>, make sure that
the water heater is not operating (stop flow).
Fan Motor
3. Increase/decrease and change the component check menu
item with the [+] / [-] button.
Gradually
increase/decrease
the speed of the
fan motor starting
from 0 RPM to full
speed and back
down to 0 RPM.
Display
The current APS value and
the current rpm value is
repeatedly displayed at
intervals of 2 seconds
4. For an item not supported by the current model, do not
display the item but skip it. (Depending on the DIP SW setting
of the main controller)
5. Press the [Info] button once to display “WAIT”, execute the
component check operation for the relevant item, and return
to the <trouble check mode> after operation ends. (Excluding
the Dual Venturi Test)
6. During the component check operation, a test is automatically
performed without pressing additional buttons (except for
Dual Venturi test).
7. The Dual Venturi Test function is to perform an On/Off manual
operation test with the [+], [-] buttons, and if the [Reset] button
is pressed or there is no key input for 5 minutes, then it returns
to the “D.VEN” display item.
Water
Adjustment
Valve
Rotates the
valve from its
current position
to fully open
(56%), then fully
closed (0%) and
then back to the
starting position
while checking
feedback.
Display of the valve close
ratio %
Display of “FEED” when
detecting the feedback
System Details
Downloaded from www.Manualslib.com manuals search engine
47
Component
Dual Venturi
Test Performed
After starting
the test, the
Dual Venturi is
turned ON, and
whenever the
[+], [-] button
is pressed, the
condition is
toggled as On →
Off or Off → On.
Display
Whenever the [+], [-] button
is pressed, the condition is
toggled as On → Off or Off
→ On
Mixing valve
(“S” models
only)
Cycles the pump
10 sec On and
5 sec OFF five
times. (Repeats
five times
for a total of
75 seconds)
Rotates the
valve from its
current position
to fully open
(56%), then fully
closed (0%) and
then back to the
starting position
while checking
feedback.
1. While in <TEST INFORMATION MENU MODE>, press the [+]/
[-] button and then press the [Info] button once when 2.OPR is
displayed on the front panel.
2. Whenever the [+] / [-] button is pressed, it increases/decreases
the operation condition and flashes at intervals of 500msec.
If the condition is not changed for 3 seconds, it works at the
displayed operation condition. (NORMAL operation condition
> 1-stage MIN > 1-stage MAX > 2-stage MIN > 2-stage MAX >
NORMAL operation condition)
3. If the [Reset] button is pressed once, then it returns to the
<TEST INFORMATION MENU MODE>. (Displayed as the
previously entered item 2.OPR)
The flow rate and ON/OFF
are repeatedly displayed at
intervals of 2 seconds
GPM icon lights when the
flow rate is displayed
Pump
(“A” models
only)
4.7.18 Operation Condition Setting
The display is the same as
the water adjustment valve.
* When selecting each test mode, the water heater performs an automatic
test and then returns to the normal operation condition. (Manual
operation required for a Dual Venturi Test)
4. If there is no button input for 3 hours, then it automatically
returns to the <Normal operation mode>.
Mode
Description
Normal
operation
condition
Operated in a normal
operation mode
1-stage MIN
operation
condition
Operated in a 1-stage
MIN operation mode
1-stage MAX
operation
condition
Operated in a 1-stage
MAX operation mode
2-stage MIN
operation
condition
Operated in a 2-stage
MIN operation mode
2-stage MAX
operation
condition
Operated in a 2-stage
MAX operation mode
Display method
4.7.19 Mixing control mode (“S” models
only)
NPE-S models have a control mode to limit the actuation of the
mixing valve, which prevents malfunction of the mixing valve
resulting from frequent operation.
To limit the mixing valve operation, follow these steps:
1. On the Front panel, press the Power button to turn off the
heater.
2. Enter the R&D information menu by pressing the Up (+) button
3 times, the Down (-) button 3 times, and then the Up (+)
button 4 more times.
48
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
3. In the R&D information menu, use the Up (+) or Down (-)
buttons to move to 2.PAR (Parameter information mode), and
then press the Info button.
No.
1
2
Mode
Mode
Description
Overshoot
mode
1. Mixing valve is
operated only when an
overshooting occurs.
2. Operation begins when
the DHW temperature
exceeds the target
temperature by
more than 14°F (8°C).
However, when the
DHW temperature
exceeds 131°F (55°C),
the mixing valve
operates to limit the
temperature to 131°F
(55°C).
Off
Mixing valve control is
not in use (fully closed at
all times)
Display method
Technical information mode
Parameter information mode
4. In the Parameter information mode, use the Up (+) or Down (-)
buttons to select P.02 (Mixing control mode) and press the Info
button to enter.
No.
Mode
1
Cascade protocol mode
2
Mixing control mode
3
Recirculation Type
Display method
Display method
4.7.20 Initial setting of a cascade system
1. At the <Normal operation mode>, press the [Diagnostic] +
[PLUS] button for over 5 seconds to set the current water
heater as the MASTER unit and to enter <Cascade setup
mode>.
5. In the Mixing control mode, use the Up (+) or Down (-) buttons
to select an option and press the Info button to set the mode.
Mode
Description
Auto
mode
(Default)
1. Switches to the
Overshoot mode if
DHW use exceeds
23,000 times in
3 months of operation.
2. Once any other mode
is selected, Auto mode
cannot be selected any
more (factory reset will
revert to the default
setting).
Normal
mode
No limitations on mixing
valve operation
Display method
2. Once in <Cascade setup mode>, it will be necessary to assign
an ID number to each slave water heater in the system. Be sure
that each slave unit has been connected using a Ready-Link
cable.
3. On each slave water heater, press the [Diagnostic] + [MINUS]
buttons for over 2 seconds to automatically receive an ID
number from the MASTER water heater. The ID number will
display on the front panel of each water heater.
4. The MASTER water heater will assign ID numbers sequentially
in the order that the slave water heaters are configured (1-15).
5. When all water heaters have been assigned an ID number,
press the [Diagnostic] + [PLUS] buttons on the MASTER unit for
over 5 seconds to complete the setup. The water heaters will
return to <Normal operation mode> and the cascade system
will be activated.
6. If the cascade setting is not completed within 1 hour, the
water heaters will revert to <Normal operation mode> and the
cascade system will not be active.
System Details
Downloaded from www.Manualslib.com manuals search engine
49
Mode
Description
Display method
MASTER icon flashing
MASTER
setting
mode
Set as MASTER
unit and assign
ID numbers to
slave units
SLAVE ID
initialization
condition
When given an
initialization
command from
the MASTER unit
SLAVE ID
assignment
condition
When given
an ID from the
MASTER unit
4.7.22 Cascade system – Master unit
replacement
Configuration with NPE units only
In order to replace the Master water heater and the controller or
change a slave unit into the MASTER unit, cancel the CASCADE
SYSTEM and then repeat the CASCADE SYSTEM initialization
procedure as described previously.
4.7.23 Cascade system – Slave unit addition
Configuration with NPE units only
ex) ID 12
4.7.21 Cancellation of a cascade system
1. If the [Diagnostic] + [reset] buttons are pressed for over
5 seconds while in <Normal operation mode> at the MASTER
unit with CASCADE turned ON, then all units in the CASCADE
SYSTEM are released and work individually.
2. In order to reset the CASCADE SYSTEM after releasing it, repeat
the CASCADE SYSTEM initialization procedure as described
previously.
3. If the [Diagnostic] + [reset] buttons are pressed for over
5 seconds while in <Normal operation mode> at the SLAVE
unit where the CASCADE communication error(E.736) occurred
with CASCADE turned ON, then the SLAVE unit is released from
the CASCADE SYSTEM and works individually.
1. In order to add an additional slave unit, connect a Ready-Link
communication cable to the new unit and wait for the MASTER
unit to automatically recognize the new unit. The slave unit will
automatically enter <SLAVE addition mode> and display SL-on the front panel.
2. At the new slave unit, press the [Diagnostic] + [MINUS] button
once to receive an ID number from the MASTER unit. The ID
number will display for 5 seconds and then return to <Normal
operation mode> linked into the CASCADE system.
Mode
Description
SLAVE
addition
mode
When connecting a
new slave unit with a
Ready-Link cable to the
CASCADE system
SLAVE ID
assignment
condition
Given an ID from
MASTER, and then
the ID is displayed for
5 seconds
Display method
ex) ID 12
NOTE
50
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
●●
NPE water heaters and NR, NP, or CH units use different
communication protocols. Therefore, an additional setup is
required when replacing an NR, NP, or CH unit in a cascade
system with an NPE water heater.
●●
When replacing an NR, NP, or CH unit in a cascade system
with an NPE water heater, the NPE unit can only be
configured as a slave unit, and one of the the NP, NR, or CH
units in the system must be configured as the master unit.
Version 2.21
Configuration with a combination of NR, NP and CH units
Follow these steps to replace an NR, NP, or CH unit in a cascade
system with an NPE water heater:
1. In the Parameter information mode, use the Up (+) or Down (-)
buttons to select P.01 (Cascade protocol mode), and then press
the Info button.
No.
1
Mode
Display method
Cascade protocol mode
NOTE
Ensure that you have properly configured the cascade protocol
settings before making any changes to the current cascade
system.
4.7.24 Cascade system – Panel [POWER]
button function
1. Press the [POWER] button once at the front panel to turn ON/
OFF each unit individually.
2
Mixing control mode
2. Press the [Diagnostic] + [POWER] button on the MASTER unit
front panel for over 5 seconds to turn ON/OFF the whole
CASCADE system.
2. In the Cascade protocol mode, use the Up (+) or Down (-)
buttons to select an option and press the Info button to set the
mode.
Mode
Description
NPE
Models
only
(Default)
The cascade system
consists of only NPE water
heater units.
Cascade
system
with NR/
NP/CH
units
The cascade system
consists of a combination
of NR/NP/CH units and
NPE water heater units.
Display method
3. The master NPE unit that is connected to the NR, NP and
CH units will come online as soon as the unit is configured
as the master unit (for NR, NP or CH units, a model-specific
configuration may be used to set them as the master units).
4. The unit ID will be initialized on the NPE unit, if “2. NR” is
selected in the Cascade protocol mode.
5. The master unit puts the NPE unit whose ID is initialized into
the slave setup mode and a new ID is assigned to the NPE
unit when you press the Diagnostic button and the Down (-)
buttons simultaneously for two seconds.
6. The master water heater periodically scans for slave water
heaters and assigns IDs (1–15) to the corresponding units in
order.
4.7.25 Recirculation type Setting
1. In the Parameter information mode, use the Up (+) or Down (-)
buttons to select P.03 (Recirculation type), and then press the
Info button.
No.
Mode
1
Cascade protocol mode
2
Mixing control mode
3
Recirculation type
(Main Controller version :
after V1.5)
Display method
2. In the Recirculation Type, use the Up (+) or Down (-) buttons to
select an option and press the Info button(or no button input
for 10 seconds) to set the mode.
No.
Mode
1
Normal
2
Special mode for preheating
Display method
7. For NR, NP or CH units, a model-specific configuration may be
used to complete the master unit configuration.
8. For details about slave ID assignment , see page 50.
3. If the [RESET] button pressed once, then it returns to the
<PARAMETER INFORMATION MENU MODE>.
* If there is no button input for 5 minutes, then automatically returns to the
<PARAMETER INFORMATION MENU MODE>.
System Details
Downloaded from www.Manualslib.com manuals search engine
51
52
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Color Code
B
B
B
B
B
B
B
B
B
B
B
B
replaced, they must be replaced
with their equivalent.
supplied with the water heater must be
GY
B
B
Water Adjustment Valve
Feedback
B
B
B
B
If any of the original wires as
Ground
M
WAV
Exhaust Thermistor
Outlet1 Thermistor
Inlet2 Thermistor
Outlet2 Thermistor
B
R
W
BK
R
W
BK
BK
BK
B
Flow Sensor
Air Pressure Sensor
High Limit S/W
: Blue
: Orange
: Red
: White
: Yellow
: Black
: Brown
: Green/Yellow
Inlet1 Thermistor
APS
B
O
R
W
Y
BK
BR
GY
BR
O
R
B
Y
R
W
BK
CON7
CON6
D
C
B
A
M
CON10
F
CON8
E
ComfortAir+
L
CON4
BK BK BK BKBK BKBK BKBK BKBK BK
CON5
CON15
BK BK BK BKBK BKBK BKBK BKBK BK
Front Panel
N
H
K
J
TB1
CON3
CON2
G
CON11
CON1
Power Switch
I
Fuse(5A)
GY
BK
W
IG
Dual Venturi
Spark
Electrode
Flame Rod
Main Gas Valve
MGV
Fan Motor
FM
Y
R OW BK
Pump
M
Hot(BK)
External
Pump
Ground
Optional
W
Y
R
W
Y
BR
B
W
BK
B
BR
W
Y
GY
Neutral(W)
Power Cord
Ground(GY)
4.8 Wiring Diagram
[NPE-180A/ 210A/ 240A]
Version 2.21
[NPE-150S/180S/ 210S/ 240S]
System Details
Downloaded from www.Manualslib.com manuals search engine
53
Color Code
High Limit S/W
: Blue
: Orange
: Red
: White
: Yellow
: Black
: Brown
: Green/Yellow
B
B
B
B
B
B
B
BR
O
R
B
Y
R
W
BK
B
B
B
B
B
B
B
Mixing Valve
Feedback
be replaced, they must be replaced
with their equivalent.
supplied with the water heater must
GY
BR
O
R
B
Y
R
W
BK
B
B
Water Adjustment Valve
Feedback
B
B
B
R
W
BK
R
W
BK
BK
BK
B
If any of the original wires as
Ground
M
MIX
M
WAV
Exhaust Thermistor
Outlet1 Thermistor
Inlet2 Thermistor
Outlet2 Thermistor
Inlet1 Thermistor
Flow Sensor
APS Air Pressure Sensor
B
O
R
W
Y
BK
BR
GY
BK BKBK
M
CON10
CON9
CON7
D
CON6
C
B
A
Front Panel
F
CON8
CON5
E
L
CON4
BKBK BKBK BKBK BKBK BK
H
K
J
TB1
Anti-Frost Heater
CON3
CON2
G
CON11
CON1
Power Switch
I
Fuse (5A)
Freeze Protect S/W
IG
BR
B
W
BK
B
BR
W
Y
Dual Venturi
Spark
Electrode
Flame Rod
M
W
Y
R
Main Gas Valve
MGV
Fan Motor
FM
Y
R OW BK
Hot(BK)
External
Pump
Ground
Optional
GY
Neutral(W)
* NPE-180S/ 210S/ 240S only
GY
W
BK
Power Cord
Ground (GY)
4.9 Ladder Diagram
NEUTRAL
3.15A
HOT
EXT_PUMP
Relay 1
EMI
FILTER
VENTURI
Relay 2
Relay 3
IGNITER
Relay 4
PUMP
PWM
FAN
Primary
Primary
SMPS
DC15V
Secondary
Speed Control
DC24V
DC12V
Water Adjust
Valve
DC5V
FSA Power
Switch
150V
Flow Control
Flame Rod
Flow Sensor
APS
H.T.L
Fan
Hall Sensor
WD-PSS
Outlet
Thermistor 1
Driving Circuit
Relay 3
Outlet
Thermistor 2
MCU 1
MGV1
MCU 2
MGV2
Inlet
Thermistor 1
Relay 1
Relay 2
Inlet
Thermistor 2
Exhaust
Thermistor
Relay 4
Communication
Interface
UART
Communication
Interface
Ready Link
Interface
FRONT
PANEL
Ready Link
[NPE-180A/ 210A/ 240A]
54
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
NEUTRAL
3.15A
HOT
EXT_PUMP
Relay 1
EMI
FILTER
* NPE-180S/ 210S/ 240S only
Relay 2
VENTURI
Relay 3
IGNITER
Relay 4
PUMP
PWM
FAN
Primary
Primary
SMPS
Speed Control
DC15V
Secondary
DC24V
DC12V
FSA Power
Switch
DC5V
Water Mixing
Valve
Flame Rod
Flow
Control
Flow
Control
Water Adjust
Valve
200V
Flow Sensor
APS
H.T.L
Fan
Hall Sensor
WD-PSS
Outlet
Thermistor 1
Driving Circuit
Relay 3
Outlet
Thermistor 2
MCU 1
MGV1
MCU 2
MGV2
Inlet
Thermistor 1
Relay 1
Relay 2
Inlet
Thermistor 2
Exhaust
Thermistor
Relay 4
Communication
Interface
UART
Communication
Interface
Ready Link
Interface
FRONT
PANEL
Ready Link
[NPE-150S/ 180S/ 210S/ 240S]
System Details
Downloaded from www.Manualslib.com manuals search engine
55
4.10 Electrical Diagnostic Points
56
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Point
Function
Wire Color
Normal Value
A
High Temperature Limit Switch
BLACK-BLACK
DC 0 V
Normally Shorted. Confirm RMS voltage.
B
APS
RED-BLACK
DC 5 V
Confirm steady voltage.
WHITE-BLACK
DC 0.3~4.5 V
C
Flow Sensor
RED-BLACK
DC 12 V
Confirm steady voltage.
WHITE-BLACK
PULSE
Check Pulse.
Cold Water-1
BLUE-BLUE
DC 0~5 V
Voltage changes according to temperature.
Hot Water-2
BLUE-BLUE
DC 0~5 V
Voltage changes according to temperature.
Cold Water-1
BLUE-BLUE
DC 0~5 V
Voltage changes according to temperature.
Hot Water-2
BLUE-BLUE
DC 0~5 V
Voltage changes according to temperature.
Exhaust Sensor
BLUE-BLUE
DC 0~5 V
Voltage changes according to temperature.
RED-BLACK
DC 12 V
Confirm steady voltage.
WHITE-BLACK
DC 0-5V
Voltage changes according to the Mixing Valve
position.
D
E
Water Adjust / Mixing Valve
Check
Voltage changes according to the APS operation.
BLUE-BROWN
F
G
H
ORANGE-YELLOW
PULSE
BLACK
0~10 uA
BLACK-RED
DC 127V~184 V
Confirm steady voltage.
BLACK-YELLOW
DC 15 V
Confirm steady voltage.
BLACK-ORANGE
DC 0~7.5 V
BLACK-WHITE
0 rpm~6500 rpm
YELLOW-WHITE
* ON : AC 96 ~138 V
Flame Rod
Fan Motor
Pump
Check Pulse.
Measure the current when the burner is operating.
Voltage changes relative to fan operation.
Check PULSE.
Confirm voltage as operating.
* OFF : 0V
* Confirm appropriate power source.
I
Power Input
WHITE-BLACK
AC 97~138 V
* Confirm the FUSE.
* Confirm the circuit breaker.
Ground Wire
GREEN-YELLOW
J
Dual Venturi
BROWN-BLUE
K
Igniter
BLUE-BLUE
L
Gas Valve
M
Front Panel
BLACK
N
Comfort Air+
BLACK
O
External Pump
Ground Wire
* ON : AC 95~120V
Check for properly grounded wire.
Confirm voltage relative to operation.
* OFF : 0V
* ON : AC 97~138 V
Confirm voltage when the unit is igniting.
* OFF : 0V
RED-YELLOW
DC 22~24 V
Confirm voltage as the Main Gas Valve 1 is operating.
WHITE-RED
DC 22~24 V
Confirm voltage as the Main Gas Valve 2 is operating.
BLACK
* ON : AC 96 ~138 V
Confirm voltage as operating.
* OFF : 0V
System Details
Downloaded from www.Manualslib.com manuals search engine
57
4.11 Key Components Description
4.11.1 PCB
Part
Function
Failure Event
Effects
Check Point
To control each component and also to check the overall performance of the unit.
Malfunctioning PCB.
A component may not operate within the unit and could produce an error code. In most cases of PCB failure, the
whole unit will not operate until the problem is resolved.
Error Code
E515, E615
Diagnostic
Visual inspection: Connection and/or breakage of wires and/or burn marks on the PCB.
Color/Number
of wires
58
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
25 (see page 40)
Version 2.21
4.11.2 High Limit Switch
Check Point
Check Point
1. Overheat prevention switch.
Function
2. If the unit detects extremely high temperatures, it will automatically trip and shut down the unit.
3. Excessively high water temperatures (more than 197.6 °F or 92 °C) in heat exchanger will activate the high
limit switch.
Failure Event
Effects
Error Code
Diagnostic
Color/Number
of wires
Unable to detect excessively high water temperature if switch fails.
Unable to shut down the water heater if the water temperature from the heat exchanger exceeds 197.6°F (92°C).
E016, E046
1. Visual inspection: Connection and/or breakage of wires.
2. Resistance check: Check range of resistance shown below.
Resistance range : under 1.0 Ω
System Details
Downloaded from www.Manualslib.com manuals search engine
59
4.11.3 Thermistor
Part
Check Point
Function
Measure inlet, outlet, and internal heat exchanger temperatures in the water heater.
Failure Event
Unable to properly measure water temperature within the water heater.
1. If any of the thermistors fail, an error code appears before starting operation.
Effects
2. If resistance values are off, the water heater will produce temperature fluctuations in hot water.
Error Code
E047, E407, E421, E432, E441
1. Visual inspection: Connection and/or breakage of wires.
Diagnostic
2. Check the resistance of the sensor (Stop operating and lower the temperature before checking).
Color/Number
of wires
Resistance range : Please refer to the table below
Wire Color: BLUE-BLUE
Inlet, Outlet
60
Exhaust Limit Temperature Sensor
Wire Color: BLUE-BLUE
Temp(°F)
Thermistor (kΩ)
Exhaust Limit Temperature Sensor (kΩ)
32~40
17.9~25.4
113.6~180.7
40~50
14.5~20.3
89.2~139.5
50~60
11.4~16.4
67.5~108.5
60~70
9.4~12.8
51.5~81.1
70~80
7.5~10.4
41.5~61.3
80~90
6~8.2
32.2~48.9
90~100
5.1~6.6
26.3~37.6
100~110
4.1~5.7
20.8~30.4
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.11.4 Fan Motor
Part
Function
Check Point
To provide combustion air into the burner and to purge exhaust flue gas.
To maintain the gas input with a long vent run, the fan operates with APS for ideal combustion.
1. Fan speed failure: the fan RPM is around 0 RPM.
Failure Event
2. The fan assembly screw is loose and/or the fan is disassembled.
3. Disconnected or defective fan connection terminal assembly.
1. Unstable combustion condition.
Effects
2. Unit vibrating and noise.
3. The water heater is not operating properly.
Error Code
Diagnostic
E109, E110
1. Visual inspection: check the fan connection wire and/or the fan mounting location.
2. Voltage check: Check range of voltage shown below.
●●
Color/Number
of wires
●●
●●
●●
Black-Red: DC 127V~184 V
Black-Yellow: DC 15 V
Black-Orange: DC 0~7.5 V
Black-White: 0 ~ 7,000 RPM
System Details
Downloaded from www.Manualslib.com manuals search engine
61
4.11.5 Flame Rod Assembly
Part
Function
Failure Event
Effects
Check Point
To ignite gas by repeatedly discharging a high voltage spark to the main burner until gas ignites.
1. Unable to ignite during the ignition process.
2. Produces multiple unsuccessful attempts to ignite.
1. The unit cannot ignite during the ignition process and “E003” or “E004” error codes will display.
2. Durability of the igniter wears down
Error Code
E003, E004, E012
Diagnostic
Visual inspection: Connection and/or breakage of wires.
Color/Number
of wires
BLACK: 0~10 uA
Bracket
Igniter
Flame rod
Gap distance : 3.5~4.5mm (1/8”)
62
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.11.6 Ignition Transformer
Part
Function
Failure Event
Effects
Error Code
Diagnostic
Color/Number
of wires
Check Point
To ignite gas by repeatedly discharging a high voltage spark to the main burner until gas ignites.
1. Unable to ignite during the ignition process.
2. Produces multiple unsuccessful attempts to ignite.
1. The unit cannot ignite during the ignition process and “E003” or “E004” error codes will display.
2. Durability of the igniter wears down.
E003, E004
1. Visual inspection: Connection and/or breakage of wires.
2. Voltage check: Check range of voltage shown below.
Blue
On : AC 97 ~ 138 V
●● Off : 0 V
●●
Input Voltage
Output Voltage
Output Current
120 V, 60 Hz
20 KV±
10mA±2mA
System Details
Downloaded from www.Manualslib.com manuals search engine
63
4.11.7 APS
Part
Function
Check Point
Detecting the air pressure entering the burner system.
1. Combustion noise occurs.
Failure Event
2. Imperfect and/or abnormal flame occurs.
3. Occurs when APS does not detect proper voltage.
Effects
Error Code
1. The water heater is not operating.
2. Produces excessive carbon monoxide emissions.
E110
1. Visual inspection: Connection and/or breakage of wires.
2. Voltage check: Check range of voltage shown below.
Diagnostic
3. Check the exhaust duct for obstruction or blockages.
4. Check the condensate trap and drain piping for obstruction or blockages.
5. Check for decreased hot water output.
Color/Number
of wires
64
●●
●●
RED-BLACK: DC 5 V
WHITE-BLACK: DC 0.3 ~ 4.5 V
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.11.8 Main Gas Valve
Part
Check Point
1. To control the amount of gas supplied to the burner based on fan speed.
Function
Failure Event
Effects
Error Code
Diagnostic
Color/Number
of wires
2. When the unit experiences abnormal combustion, it shuts off the gas valve automatically and prevents
unsafe situations.
Unable to open/close
1. No flames.
2. No operation of the unit.
E003, E012
1. Visual inspection: Connection and/or breakage of wires.
2. Voltage check: Check range of voltage shown below.
●●
●●
RED-YELLOW: DC 22~24 V
WHITE-RED: DC 22~24 V
Test Pout with
manometer for
specified pressure
range to ensure
that the Gas Valve is
operating properly.
System Details
Downloaded from www.Manualslib.com manuals search engine
65
4.11.9 Burner
Part
Function
Check Point
1. Pre-Mix system reduces emissions and increase efficiency.
2. The burner facilitates the air/gas mixture necessary to produce the proper heat during combustion.
1. Unable to initialize/sustain combustion.
Failure Event
2. Dust or soot deposit on the burner surface
3. Possible gas leakage from burners.
1. Abnormal combustion.
Effects
2. Unstable flame conditions and/or flame loss.
3. Ignition failure.
Error Code
E003, E004, E012
Diagnostic
Visual inspection: Excessive deposits on the burner surface and/or unstable flame conditions during operation.
Color/Number
of wires
N/A
Burner Body
(Fuel Gas +
Combustion Air Mix Zone)
Combustion Air Supply
Fuel Gas Supply
66
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.11.10 Water Adjustment Valve
Part
Function
Failure Event
Check Point
To control the water flow to maintain steady hot water temperatures.
The valve cannot modulate or open/close in CASCADE mode.
1. Water Adjustment Valve is not operating properly.
Effects
2. Abnormal flow detected during normal operation. “E434” displayed.
3. Temperature fluctuations at the hot water outlet.
Error Code
Diagnostic
E434
1. Visual inspection: Connection and/or breakage of wires. Clean the Domestic cold water inlet filter.
2. Voltage check: Check range of voltage shown below.
●●
Color/Number
of wires
●●
●●
RED-BLACK: DC 12 V
WHITE-BLACK Start position: DC 0 V
Any open position: DC 5 V
BLUE-BROWN: PULSE
ORANGE-YELLOW
OUT
IN
System Details
Downloaded from www.Manualslib.com manuals search engine
67
4.11.11 Flow Sensor
Part
Function
Failure Event
Effects
Error Code
Diagnostic
68
Check Point
To detect water flow in GPM (Gallons Per Minute) for steady hot water temperatures.
1. Unable to detect or measure water flow rate.
2. Damage to and/or water leakage from the water flow sensor.
Ignition sequence does not start.
E439
1. Visual inspection: Connection and/or breakage of wires.
2. Visual Inspection: Check for damage and/or scale formation on sensor.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
4.11.12 Primary Heat Exchanger
Part
Check Point
1. Main part for heat transfer from the burner.
Function
Failure Event
Effects
Error Code
Diagnostic
2. There are multiple paths of water pipes on the heat exchanger surface as well as inside the combustion
chamber which minimizes the heat loss.
1. Water and/or exhaust gas leakage through a crack.
2. Improper heat transfer can cause the water in the heat exchanger to boil due to possible scale formation.
1. Exhaust gas leakage.
2. Excessive heating of the water that produces boiling noises.
E016, E030, E047
1. Visual inspection: Check if there is a crack on the surface of heat exchanger.
2. Sound inspection: Check if boiling occurs inside the unit.
Color/Number
of wires
N/A
System Details
Downloaded from www.Manualslib.com manuals search engine
69
4.11.13 Secondary Heat Exchanger
Part
Check Point
1. Main part for heat transfer from the burner.
Function
Failure Event
Effects
Error Code
Diagnostic
2. There are multiple paths of water pipes on the heat exchanger as well as inside the combustion chamber
which minimizes heat loss.
1. Water and/or exhaust gas leakage through a crack.
2. Improper heat transfer can cause the water in heat exchanger to boil.
1. Exhaust gas leakage.
2. Excessive heating of the water that produces boiling noises.
E016, E030, E047
1. Visual inspection: Check if there is a crack on the surface of heat exchanger.
2. Sound inspection: Check if boiling occurs.
Color/Number
of wires
70
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
N/A
Version 2.21
4.11.14 Buffer Tank (“A” models only)
Part
Function
Failure Event
Effects
Check Point
To provide hot water at a steady temperature and to operate without a minimum flow rate with the use of the
internal circulation pump.
Cracking and/or water leakage due to wear.
Temperature fluctuations in the hot water outlet and/or leaking.
Error Code
Diagnostic
N/A
Visual inspection : Check the mini buffer tank for any cracks.
Color/Number
of wires
N/A
System Details
Downloaded from www.Manualslib.com manuals search engine
71
4.11.15 Circulation Pump (“A” models only)
Part
Check Point
1. Pump operates when using internal or external hot water circulation.
Function
Failure Event
2. Internal circulation will minimize the effect of temperature fluctuations and external circulation delivers hot
water to fixtures quickly resulting in water conservation.
Unable to detect or measure water flow rate when the pump is called to operate.
1. The water heater freezes.
Effects
2. Temperature fluctuations when the water heater is set to internal recirculation.
3. Hot water is not quickly available at fixtures when the water heater is set to external recirculation.
Error Code
E438
Diagnostic
1. Visual inspection: Check the circulation pump connection wire.
* Check for blocked/clogged water filter.
2. Voltage check: Check range of voltage shown below.
Color/Number
of wires
72
YELLOW-WHITE
ON : AC 96 ~138 V
●● OFF : 0V
●●
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
5. Troubleshooting
5.1 Error Code List
Error Code
Sub
Code
Function
Self-diagnostic/Action
E003
0
Ignition failure
* Check to see if the main gas supply valve is open.
* Verify that gas pressure is within operating range.
* Check gas system and orifice.
* Check Dual Venturi for proper operation.
* Check for proper dipswitch settings (see page 20).
* Tighten the ground connection screws on heat exchanger.
E004
0
FALSE flame detection
* Ensure ground wire is connected.
* Check the igniter for spark.
Flame loss
* Check the main gas line (Is the valve open?).
* Verify gas pressure is within operating range.
* Check gas meter for proper BTU capacity.
* Check flame rod and verify [J] value in DIAGNOSTIC mode.
* Check intake air filter.
* Check ground wire.
* Check power supply.
* Tighten the ground connection screws on heat exchanger.
Overheating of heat exchanger
* Clean the inlet water filter.
* Check High Limit Switch.
* Check for proper dipswitch settings (see page 20)
* Check the water adjustment valve.
* Check the heat exchanger; a flush may be necessary.
* Check pump operation (for A models only).
* Turn OFF the system for at least 30 minutes then restart.
0
Exhaust Overheat: exhaust limit sensor shuts down
the unit when the flue temperature exceeds 230 °F
(110 °C) for more than 10 seconds.
* Turn OFF the system for at least 30 minutes then restart.
* Clean the inlet water filter.
* Check exhaust thermistor and verify [K] value in
DIAGNOSTIC mode.
* Check for proper dipswitch settings.
* Check the water adjustment valve.
* Check the heat exchanger; a flush may be necessary.
1
Abnormal exhaust thermistor (open)
* Check exhaust thermistor connection.
2
Abnormal exhaust thermistor (short)
* Check for proper connection to the PCB.
1
Abnormal Dual Venturi Limit Switch operation (ON)
* Check the Dual Venturi connection.
2
Abnormal Dual Venturi Limit Switch operation
(Close OFF)
* Test Dual Venturi for proper operation using TEST mode.
3
Abnormal Dual Venturi Limit Switch operation
(Open ON)
* Check gas orifice for obstructions.
0
Abnormal fan motor activity
* Check and clean the intake air filter.
* Verify proper voltage and wire connection.
* Check and clean the fan motor.
1
Exhaust blockage (checking the FAN)
* Check the intake/exhaust/condensate drain pipe for
obstructions.(ice, snow, wildlife, etc)
2
Exhaust blockage (Using hot water)
* Check and clean the intake air filter.
3
Exhaust blockage (using space heating)
* As a temporarily solution for troubleshooting purposes,
restart the unit and/or remove the front cover.
E012
E016
E030
E047
E060
E109
E110
0
0
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
73
Error Code
Sub
Code
E407
E421
E432
E434
Function
Self-diagnostic/Action
1
Abnormal Hot water outlet thermistor (Open)
2
Abnormal Hot water outlet thermistor (Short)
●●
1
Abnormal Cold water inlet thermistor (Open)
●●
2
Abnormal Cold water inlet thermistor (Short)
1
Abnormal Cold water inlet2: thermistor (Open)
2
Abnormal Cold water inlet2: thermistor (Short)
1
Abnormal water adjustment valve. (Open)
2
Abnormal water adjustment valve. (Close)
●●
●●
●●
0
Abnormal circulation pump. ("A" models only)
●●
●●
Check the water adjustment valve.
●●
●●
Check the circulation pump.
Check water filter for blockage.
Check the flow sensor.
Check the cold water main line.
Set to Internal Recirculation mode and verify flow rate.
●●
●●
●●
E439
E441
E445
0
Abnormal flow sensor
●●
Check the flow sensor.
1
Abnormal Hot water inlet2: thermistor(Open)
●●
Check the thermistor.
2
Abnormal Hot water inlet2: thermistor(Short)
●●
Replace the thermistor.
1
Abnormal mixing valve(Open)
2
Abnormal mixing valve(Close)
●●
Check the mixing valve.
Abnormal communicatin between PCB and Ignitor.
●●
Check the PCB.
8
Abnormal communication between PCB and
Ignitor
●●
Check the PCB connection.
Check the Ignitor.
9
Abnormal communication between PCB and FAN
10
Abnormal monitoring device of PCB
1~7
E515
11~12
●●
●●
●●
●●
●●
Check the PCB connection.
Check the Fan.
Check the PCB connection.
Check the Dual Venturi.
Abnormal communication between PCB and Dual
Venturi
●●
●●
Check the PCB connection.
Check the Dual Venturi.
E517
0
Abnormal dip switch setting
●●
Check the dip switches on the front panel and PCB.
E593
1
Abnormal panel key
●●
Check the Panel.
0
Abnormal input data from High limit switch of Heat
exchanger
●●
Check the PCB.
1
Abnormal input data from exhaust sensor
●●
Check the exhaust sensor wiring connection.
Check the exhaust sensor.
2
Abnormal input data from flame rod
E594
3~14
15
16
74
Check the thermistor.
Verify [C] value in DIAGNOSTIC mode.
Replace the thermistor.
Check the thermistor.
Check thermistor voltage and resistance values.
Replace the thermistor.
●●
●●
E438
Check the thermistor.
Replace the thermistor.
●●
●●
Check the flame rod wiring connection.
Check the flame rod.
Abnormal memory of PCB
●●
Check the PCB
Below the range of input data from Pressure sensor
●●
Check the Pressure sensor wiring connection.
Check the output voltage of pressure sensor.
Over the range of input data from Pressure sensor
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
●●
●●
Version 2.21
Error Code
E615
Sub
Code
Function
0
Abnormal input data from High limit switch of Heat
exchanger
1
Abnormal input data from exhaust sensor
2
Abnormal input data from flame rod
Self-diagnostic/Action
●●
Check the PCB.
●●
Check the exhaust sensor wiring connection.
Check the exhaust sensor.
●●
●●
Check the flame rod wiring connection.
Check the flame rod.
Abnormal memory of PCB
●●
Check the PCB.
15
Below the range of input data from Pressure sensor
●●
16
Over the range of input data from Pressure sensor
Check the Pressure sensor wiring connection.
Check the output voltage of pressure sensor.
3~14
●●
●●
●●
E736
0
Abnormal cascade communication
●●
●●
Check the Ready-Link cable.
Check the cascade settings.
Check PCB version for compatibility.
1
Abnormal outdoor temperature sensor (Open)
(appears only when the outdoor reset curve is
enabled).
●●
2
Abnormal outdoor temperature sensor (Short)
(appears only when the outdoor reset curve is
enabled).
E760
0
Flushing/service alarm
●●
A heat exchanger flush is necessary.
E782
0
Abnormal Main-Panel communication
●●
Check the PCB.
E785
0
Abnormal Flow Switch Operation
●●
Check the Cold Water line.
Check the Flow Switch connection.
E740
●●
●●
1. Ensure that the outdoor reset curve is configured
properly.
2. Check the outdoor temperature sensor wiring
connection.
If any of the above solutions do not resolve the problem with the Water Heater, contact Navien’s Technical department at 1-800-519-8794.
There will be error codes displayed on the front panel and recorded on the PCB board (within the unit) of any problems or failures that occur
with the Water Heater.
IMPORTANT
To reset the Water Heater, either press the [Reset] button on the front panel or disconnect, then reconnect electrical power to the water
heater.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
75
5.1.1 003Error
Error occurrence conditions and check items
Error
Description
E03
Ignition failure
In the case of an ignition failure, the water heater will attempt ignition 10 times. If no flame is detected, the system
displays the error message 03E (manually cleared) on the remote controller.
1. Check if the gas supply valve is open and for proper supply pressure.
2. Check the electrode gap, electricity discharge, or deformation of the flame rod.
3. Check the operation of the ignition transformer (ignition state, input power (AC 102~132 V)
4. Check the operation of the gas control valve (DC 22~24 V, coil short circuit, solenoid valve).
5. Check the flame rod, wiring and grounding.
6. Check if the air pressure hose is broken or clogged.
Check items
7. Check if the air pressure sensor works properly.
8. Check the PCB DIP switch settings.
9. Adjust the offset pressure (see page 29).
10. Check the gas orifice plate for the proper gas type.
11. Check the flue and air supply for any collected water (for vertical vent installations).
12. Tighten the ground connection screws on heat exchanger.
13. If the issues continue despite checking the items above, replace the PCB.
Scenario1
Is the igniter
operating normally?
NO
Does the igniter have
proper voltage?
Yes
Yes
Is the igniter
electrode clean?
Is the igniter electrode
damaged?
NO
Check connector
Check the voltage between #1 and #4 of CON 3:
Same as supply voltage (97 – 138 VAC)
(see page 52 for Wiring Diagram)
NO
Clean or replace igniter
electrode
Yes
Check the gas valve assembly
76
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Replace igniter assembly
Version 2.21
Scenario2
Is gas valve operating
normally?
NO
Does the main
gas valve have proper
voltage?
Yes
Yes
Is gas valve open?
Yes
Check the flame rod
NO
Check connector
Check the voltage between #1 and #3 of CON 4:
22-24 VDC
Check the voltage between #2 and #3 of CON 4:
22-24 VDC
(see page 52 for Wiring Diagram)
NO
Check that gas valve is open or
check LP supply
In case of LP gas model, low gas pressure can cause
“Ignition Failure”.
* Normal gas pressure: 8.0 - 13.0" w. c.
Power OFF the unit
Scenario3
Is the flame detection
device normally
operating?
NO
Yes
Restart unit
Is the flame current
detected?
Yes
NO
Clean or replace the flame rod
Check whether ground circuit is
properly installed.
Check the current #1 of CON 10: 1 - 20μA
(see page 52 for Wiring Diagram)
Check connector
(#1 of CON10)
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
77
Check method
Failure mode
Cause
Check method
1. Check if the main gas valve is open.
2. Check the gas supply pressure.
●● NG: 3.5” - 10.5” W.C, LP: 8” - 13” W.C
●● LP pressure drop occurs frequently in the winter.
3. Check the flexible pipe diameter for compatibility with the water heater.
4. While the static pressure is normal, the use of another gas appliance may cause
a possible drop in gas pressure to the unit. Therefore, it is required to check the
dynamic pressure.
●● Static pressure: Gas pressure during stand by.
●● Dynamic pressure: Gas pressure at max combustion. (2nd stage MAX combustion
setting: DIP S/W 1-1 ON)
Gas supply error
5. If a CSST connector has been used, check to ensure that it is not been overtightened
resulting in the seal obstructing gas flow.
6. Check the meter class (Example)
●● Gas meter
Water heater Furnace Domestic gas stove
●● 425 CFH (Gas Meter) ≥ 195 CFH (Water Heater)+ 58.8 CFH (Furnace)
+ 63.7 CFH (Domestic gas stove)
 1 CFH = 1,020 Btuh
Ignition failure
Digital pressure
manometer
Check gas supply pressure(Refer to page 24)
Defective electrode
gap and shape
78
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
A shifted seal narrows the inner diameter of CSST
connector
Defective electrode gap and shape disables ignition.
Appropriate electrode gap: approx. 3~4mm(1/8") (replace if defective)
●● An ignition fail may occur due to improper gap, while discharge seems normal when
checked via the flame monitoring window. Therefore, it is required to check the gap
after disassembly.
●●
Version 2.21
Failure mode
Cause
Check method
Electrode gap 3.5~4.5mm(1/8")
Ignition failure
No spark from
electrode
Electrode gap error
When no spark is made from the electrode at ignition:
●● Remove the electrode and check if there is a crack on the insulator.
●● Adjust the gap if there is a discharge of electricity from the metallic part of the
burner.
●● Ensure that the insulating gasket is installed between the electrode and burner
casing.
●● Check the input power to the ignition transformer (AC 102 ~ 132 V).
●● If there is sufficient power to the ignition transformer, replace the ignition
transformer.
●● Replace the PCB if there is no power or insufficient power supplied to the ignition
transformer.
●● Check the insulator boots on the spark wires for cracks/holes.
Ignition transformer
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
79
Failure mode
Cause
Check method
1. Check the primary/secondary power supply to the main gas valve.
●● Check, with a multimeter, if the input power is DC 22-24 V.
Main gas valve
2. Replace the PCB if power is not supplied.
3. If power supply is normal, check if the coil is open.
4. Check if the solenoid valve works properly.
●● Feel or hear a click.
Ignition failure
Gas block
Check if the coil is open
Check the voltage of the solenoid valve /
White-Yellow , White-Red
1. Check the location of the flame, if there is any deformation or foreign substance,
repair or replace the part.
2. Check the flame rod wire for proper connection and/or damage.
Flame sensing error
3. Check the grounding to the water heater case to verify proper grounding at the
outlet.
●● If the ground wire is improperly connected or not making a good connection,
remove and reattach the ground wire ensuring good contact with the case.
●● Or use a multimeter to measure the flame sensing current (normally 3~4 µA).
Repeated ignition-out
Measuring flame current
80
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Grounding wire position
Version 2.21
Failure mode
Cause
Flame loss and noise
occurs at ignition
Check if there are any
blockages in the gas
orifice plate.
Improper air intake air
supply
Rainwater intrusion
Check method
Ignition failure will occur if the gas orifices are clogged.
●● Remove the gas inlet pipe and check the orifice plate.
Check if rainwater has collected inside the unit from an improperly installed air intake
pipe.
Tighten the ground connection screws on heat exchanger.
Other trouble
Screw loosening
Defective PCB
If the issue continues despite checking above items, replace the PCB.
5.1.2 004Error
Error occurrence conditions and check items
Error
E04
False-flame detection
Description
1. Pre ignition false-flame
If a flame signal is detected continuously for 3 seconds before combustion (stand-by, pre-purge, preignition), a false-flame error 04E (automatically cleared) is displayed on the front panel and the system
performs continuous post-purge and operates the pump.
2. Post purge false-flame
If a flame signal is detected continuously for 3 seconds when the system performs post-purge as fuel supply
is stopped, a false-flame error 004E (automatically cleared) is displayed on the front panel and the system
performs continuous post-purge and operates the pump.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
81
Error
Description
1. Check if gas leaks due to defective seals on the main gas valve.
Check items
2. Check if proper spark is discharged from the electrode.
3. Check if gas is supplied within the proper pressure range.
4. Check the PCB and replace if defective.
Is the flame detected in
the burner when there is
no ignition?
NO
Clean or replace flame rod
Check the current #1 of CON 10:1 - 20μA
(see page 52 for Wiring Diagram)
Yes
External noise current
Check method
Failure mode
Cause
Check method
Flame before/after
combustion
Leakage from main gas
valve
Replace the gas flame if flame occurs before combustion or if there is remaining flame
after combustion is stopped.
Discharge of electricity
from electrode
●●
Error before/after
combustion
Other trouble
82
Gas valve
Defective PCB
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Spark discharges from electrode to flame sensor at ignition.
Replace or correct location of flame detecting rod.
Gas may leak as the main gas valve is pushed by the gas supply over the standard
pressure.
●● Check the supply pressure: NG: 3.5" ~ 10.5” WC, LP: 8.0" ~ 13.0"W.C
●● If the gas pressure is too high, notify the gas supplier about the issue, and if
necessary, replace the gas valve.
●● If there is a gas leak close the gas supply valve and repair the unit before using the
system.
If the issue continues despite the checking of items above, replace the PCB.
Version 2.21
5.1.3 012Error
Error occurrence conditions and check items
Error
E012
Flame loss
Description
If the system detects loss of flame during combustion, the system stops supplying fuel, attempts to restart,
counts the incidents of flame loss, and if the incident occurs 20 times consecutively displays 012E (manually
cleared) on the front panel.
1. Measure, with a manometer the gas supply pressure (NG: 3.5" ~ 10.5” W.C, LP: 8”~ 13.0" W.C)
2. Check the Gas meter Capacity.
3. Tighten the ground connection screws on heat exchanger.
Check items
* Check the flame detection
AD value for proper resistance.
(refer to page 42~43)
4. Check if the gas orifice is clogged.
5. Check if the PCB is working properly.
Does the
water heater have
sufficient gas
pressure?
Yes
NO
Check the gas pressure
Gas Pressure
Natural Gas: 3.5” - 10.5” W.C.
LP Gas: 8.0" - 13.0" W.C.
Check connector
(#1 of CON10)
see page 52 for Wiring Diagram
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
83
Check method
Fault
Possible
Causes
Check method
1. Check the gas supply pressure.
●● NG: 3.5” - 10.5” W.C, LP: 8” - 13” W.C
●● LP pressure drop occurs frequently in the winter.
2. While the static pressure is normal, the use of another gas appliance may cause a possible
drop in gas pressure to the unit. Therefore, it is required to check the dynamic pressure.
 Check the static pressure: Gas supply pressure during stand by.
Check the dynamic pressure: Gas supply pressure at (2nd stage MAX combustion setting:
DIP S/W 1-1 ON) MAX combustion
Flame loss and noise
occurs after ignition
Low gas
supply
pressure
3. Check the gas pipe connector.
●● If a CSST connector has been used, check to ensure that it is not been overtightened
resulting in the seal obstructing gas flow.
4. Check the gas meter capacity (Example)
●● Gas meter Water heater Furnace Domestic gas stove
425 CFH (Gas Meter) ≥ 195 CFH (Water Heater)+ 58.8 CFH (Furnace)
+ 63.7 CFH (Domestic gas stove)
 1 CFH = 1,020 Btuh
5. If too much pressure is exerted on the nut component while installing the gas pipe may
reduce the gas supply due to packing push-out and Teflon blockage, etc.
84
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
85
Fault
Possible
Causes
Check method
Model
Gas Type
Offset
NG
-0.04"±0.01"
LP
-0.03"±0.01"
NPE-180A
NPE-180S
NG
-0.04"±0.01"
LP
-0.03"±0.01"
NPE-210A
NPE-210S
NG
-0.04"±0.01"
LP
-0.02"±0.01"
NPE-240A
NPE-240S
NG
-0.04"±0.01"
LP
-0.02"±0.01"
NPE-150S
Flame loss and noise
occurs after ignition
Check the offset values for low fire
Offset value for low fire
Replace the electrode or clean the fire detecting electrode.
-- Cause: Due to the properties of the electrode, the oxide film is created due to
long-term exposure to the high temperature; therefore, errors may be caused in
detecting the fires.
-- Check-up: Use sandpaper to clean the fire detecting electrode covered with oxide
film or replace it.
Flame Rod
(Electrode)
86
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Fault
Possible
Causes
Check method
Check the tightness of the screw or ground bolt in the Chamber + SC heat exchanger.
-- Cause: Screw or ground bolt in the chamber and SC heat exchanger can be
loosened by the vibration or external impact when operating the boiler (water
heater).
-- Check-up: A failure in the current flow between the chamber and burner may cause
the flame-out; therefore, the tightness (fastened) of the screw needs to be checked.
[Fasten the ground screw (2EA) after fastening the assembly screw (3EA) in the front
of the heat exchanger]
Tightness of Screw or
Ground Bolt
[Location of assembly screw and ground bolt in heat exchanger]
Defected metal fiber
Flame loss during 2nd
stage
Blockage
in the gas
orifice plate.
Other trouble
Defective
PCB
1 Check the presence of debris in the metal fiber.
2 Check the sagging of the metal fiber and then the gaps with the electrode.
[Gap between the electrode and metal fiber: 12mm]
Flame loss will occur if the gas orifices are clogged.
●● Remove the gas inlet pipe and check for debris; remove and clean the orifice plate if necessary.
If the issue continues despite checking above items, replace the PCB.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
87
5.1.4 016Error
Error occurrence conditions and check items
Error
E16
Bimetal overheated
Check items
Description
If the overheat controller on the heat exchanger is initiated during combustion/standby of the water heater, the
system displays the 016E (manually cleared) message on the front panel. The water heater switches into LockOut, and performs post-purge continuously and operates the pump.
1. Check if the overheat controller is working properly.
* Check resistance value or continuity. (refer to page 59)
2. Check the hot water temperature sensor. (refer to page 60)
Is HTL* normally
operating?
NO
Replace HTL
* HTL: High Temperature Limit Switch
Yes
Check the resistance between #1 and #2 of
CON 6: short-circuit
Measuring should be done at least 30 minutes
after error.
Is HTL* normally
operating?
Yes
1 step: Flushing, Clean Filter
2 step: Try to restart
NO
Check connector
(#1 and #2 of CON 6)
88
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Check method
Fault
Possible Causes
Check method
Defective overheat
controller
Check if the contact point of the overheat controller is defective.
●● Use a multimeter to see if the resistance is normal (0.3Ω) or abnormal (∞).
Defective safety device
Overheat controller
Temperature sensor
error
Defective hot water
output temperature
sensor
Check if the overheat controller wire is
disconnected ( Normal 0.3Ω )
1. If the hot water temperature is sensed lower than it actually is due to a defective
sensor, check if the deviation of temperature is large due to a defective
temperature sensor.
●● Check the output temperature displayed on the front panel.
2. Measure the temperature sensor resistance, and determine if the sensor is
defective.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
89
Fault
Possible Causes
Check method
1. If the Max switch #1 of 1-1 is on,
Set the switch to the normal operation position.
Capacity setting
●●
2. PCB DIP S/W capacity setting error can suddenly increase the hot water
temperature.
Check the PCB DIP S/W capacity setting.(refer to page 21)
DIP SWITCH 1-1
DIP SWITCH 1-2
ON
NPE-150
1
2
3
4
5
6
DIP S/W 1-1
ON
NPE-180
NPE-210
ON
1
1
2
3
4
3
4
5
6
2
3
4
5
6
2
3
4
5
6
ON
1 2 3 4
1 2 3 4 5 6
ON
1
Other trouble
2
DIP S/W 1-2
ON
ON
NPE-240
1
●●
2-switch Panel:
Switch
Function
1
Cascade Vent
2
Gas Type
Setting
Common Vent
1-OFF
Individual Vent
1-ON
Natural Gas
2-OFF
Propane Gas
2-ON
ON
1
90
ON
2
3
4
5
6
7
8
9
10
Primary heat
exchanger overheated
The surface temperature rises due to heavy scale deposits in the primary heat
exchanger.
●● Flush the primary heat exchanger.
Defective PCB
If the issue continues despite checking the items above, the PCB is defective.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
5.1.5 030Error
Error occurrence conditions and check items
Error
Description
If the overheat controller on the top of the exhaust duct is initiated, the system displays the heat exchanger
bimetal overheat message 30E (cleared manually) on the front panel.
The water heater switches into Lock-Out, and performs post-purge continuously and operates the pump.
Overheating controller operates when the temperature exceeds 230°F (110°C) for 10 minutes or over.
E030
Exhaust gas
temperature error
1. When the conroller detects the exceeding temperature of 230°F (110°C) for 10 minutes or over, "E030" error
code will display and perform post-purge. → Automatically cleared.
2. When the controller detects the exceeding temperature of 140°F (60°C) while performing post-purge.
→ Manually cleared.
3. When the conroller detects the exceeding temperature of 230°F (110°C) for 10 seconds or over three times or
more after the error is automatically cleared. → Manually cleared.
Check items
1. Check if the overheat controller operates normally.
2. Check if the PCB works properly.
Is exhaust thermistor
normally operating?
Yes
NO
Check the exhaust thermistor
Check the resistance between #9 and #10 of CON 7:
short-circuit (check page 52 for Wiring Diagram)
Check the heat exchanger
Check for leakage in the
combustion chamber
Flush heat exchanger
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
91
Check method
Fault
Heat exchanger
overheated
Possible Causes
Damaged or clogged
heat exchanger
Check method
1. The error occurs due to high exhaust gas temperature caused by a damaged or
clogged heat exchanger.
2. Flush the heat exchanger to remove scale deposits.
3. Replace the heat exchanger if it is damaged or cannot be unclogged.
Defective overheat
controller
Defective contact point of the exhaust gas overheat controller 230°F (110°C) Max
●● Check connection of the overheat controller.
●● If the resistance is abnormal, replace the temperature sensor. (refer to page 60)
●● Check the output temperature displayed on the PCB.
Defective part
Check if the hot water temperature sensor is open (Error type : MΩ Open)
Other trouble
92
Defective PCB
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
If the issue continues despite checking the items above, replace the PCB.
Version 2.21
5.1.6 046Error
Error occurrence conditions and check items
Is heat exchanger
thermistor normally
operating?
Yes
Check connector
( #1 and #2 of CON 6)
NO
Is resistance
within normal range?
(refer to page 59)
Yes
1 step: Flushing, Clean Filter
2 step: Try to restart
3 step: Replace PCB
NO
Replace heat exchanger
thermistor.
5.1.7 047Error
Error occurrence conditions and check items
Is exhaust thermistor
operating normally?
Yes
NO
Replace exhaust thermistor
Resistance between #9 and #10 of CON6 is from 2kΩ
to 300kΩ at normal condition. (see page 52 for
Wiring Diagram)
Check connector
(#9 and #10 of CON6)
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
93
5.1.8 060Error
Error occurrence conditions and check items
Error
Description
E060
Dual Venturi error
This error message is displayed on the front panel if the wiring is disconnected or the Dual Venturi malfunctions.
The water heater switches into Lock-Out, and performs post-purge continuously and operates the pump.
Check items
1. Check that the Dual Venturi is operating correctly.
2. Check that the wiring harness is connected correctly and the cables are not damaged.
Is Dual venturi ON?
Is Dual venturi OFF?
Is Dual venturi
closed?
Yes
Reset the Unit
Is Dual venturi open?
Yes
Reset the Unit
NO
NO
Is Dual venturi
repeatedly open and
closed?
Yes
Replace the Dual venturi
Is Dual venturi wire
normal?
NO
NO
Check the Dual venturi
wire
Replace the controller
Yes
Is Dual venturi
repeatedly open and
closed?
Yes
Replace the Dual venturi
NO
Replace the controller
Dual venturi OFF
94
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Dual venturi ON
Version 2.21
Check method
Fault
Possible Causes
Defective Dual Venturi
cable or harness
Check method
1. Disconnect all cables from the Dual Venturi.
2. Using a multi-meter, test the Dual Venturi electrical wiring.
1. Turn off the power to the unit using the main power switch (do not use the front
panel power button) and wait for 10 seconds.
2. Turn on the power.
3. Wait until Fan Auto Adjusting is complete.
Dual Venturi action
error
Dual Venturi not
operating
4. Enter the Dual Venturi Test Mode and perform a test.
1) Repeat the test at least twice. Turning the unit ON and OFF once makes one test
cycle. ON → OFF → ON → OFF → …… is the minimum sequence.
2) Confirm that the Dual Venturi is operating correctly.
a. Listen to the Dual Venturi while it is running and check for operational noise
(clicks at unit ON and unit OFF).
b. If operational noise cannot be heard because of ambient noise, disassemble
the Dual Venturi and perform a visual inspection.
5. If error message (E060) occurs, replace the Dual Venturi.
6. If a Dual Venturi error does not occur, replace the APS.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
95
5.1.9 109Error
Error occurrence conditions and check items
Error
Description
The system checks the RPM signal after the fan starts to run, and displays the error message 109E (cleared
manually) in the following cases:
E109
Fan motor RPM error
1. If the RPM remains low or close to 0, the system determines RPM error, and the water heater switches into
Lock-Out (gas valve and ignition transformer locked). (However, the air pressure sensor should be normal.)
2. If the RPM signal of low or close to 0, is detected for 3 seconds during combustion, the system stops
combustion, and the water heater switches into Lock-Out. (However, the air volume sensor should be
normal.)
1. Check if the fan motor works normally using the component test mode (refer to page 47).
2. Check the power supply to the fan (Black + Red, approx. DC 127~184 V)
Check items
3. If RPM is significantly low while the fan works and the power supply is normal, replace the fan motor.
4. If the fan connector is wet due to any reason including leakage, take corrective action by powering the unit
OFF, then drying the components completely before continuing operation.
5. Check for loose connection of white connector that attaches the fan motor to the PCB.
Does the fan motor
have nominal operation
voltage?
Yes
Is there any voltage from
the fan motor?
Yes
NO
Check power and connector
Check the voltage between #3 and #5 CON 11:
127-184V DC (check page 52 for Wiring Diagram)
NO
Check the PCB
Check the voltage between #3 and #7 CON 11:
0-7.5V DC
Check fan assembly
96
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Check method
Fault
Possible Causes
Check method
1. Check the power supply to the blower.
●● Black+Red, approx. DC 127~184 V
No fan operation
2. Replace the PCB if voltages are abnormal. (When replacing the PCB, turn off the
unit and then wait for at least 10 seconds before proceeding.)
3. If the issue continues despite the checking the items above, replace the fan motor.
Fan action error
Check if the fan motor wire is disconnected
Fan motor RPM error
Defective rotator
1. If RPM is significantly low while the fan is operating and the power supply is
normal. Follow the instructions listed below and replace the fan.
1) Unplug the power cable to the unit and then wait for 10 seconds until the
remaining SMPS voltage completely discharges.
2) Disconnect the fan cable and then re-connect it.
3) Plug the power cable and turn on the unit.
4) Fan Auto Adjusting verifies error conditions for error code E109. If an E109 error
occurs, enter the Fan Test Mode and verify fan RPM and APS input voltage.
(Display: ex. H.320 = 3200 RPM)
5) If RPM is low or there is a sensor circuit error, replace the fan.
Connection and disconnection of the fan cables while the unit is ON
may cause electrical damage to the fan drive circuit or main PCB.
2. If the issue continues despite checking the items above, replace the PCB.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
97
5.1.10 110Error
Error occurrence conditions and check items
Error
Description
The system senses the air volume and the RPM signal, and displays 110E on the front panel in the following cases:
E110
Air pressure error
1. When the initial fan auto-adjust is not performed.
2. When the unit capacity reaches up to 95% of the maximum heat during combustion, and APS is not up the
standard value.
1. Check if the venturi (burner) hole is clogged.
2. Check if the condensation drain line or the drain is clogged.
Check items
3. Check the flue and exhaust to verify proper installation and clearances. (Circulation of exhaust gas generates
noise.)
4. Check if the air supply/exhaust flue is clogged (rainwater may collect inside from an improperly installed air
supply/exhaust pipe).
5. Defective air pressure sensor or PCB.
Is there any restriction
in airflow?
NO
Reset or Restart
Yes
Remove all the restrictions in
airflow around unit and check
the vent pipe for obstructions.
98
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Check method
Fault
110E
Exhaust blockage
Check method
Possible Causes
Abnormal flow of
intake air supply /
exhaust
1. If 110E occurs intermittently during ignition or combustion, compare the standard
RPM with the current RPM at Min / Max combustion (dip switch 1-1&1-2). If the
current RPM is higher than normal, check the following:
●● Air supply / exhaust vent for any blockages.
●● Blocked condensate drain
●● If the air pressure sensor hose is broken or clogged.
2. Replace the old PCB with the latest version.
Condensate drain error
Defective air supply/
exhaust flue
Condensate drain error
Exhaust air is blocked due to condensate drain error.
●● Check if the condensate hose or the siphon is frozen.
●● Check if the condensate hose is kinked.
●● Remove bottom of trap and verify it is not blocked.
Deformed or clogged
flue
1. Check the exterior of the flue for damage and obstructions.
Exhaust gas flows in
through the supply
pipe
If the exhaust gas enters into the air supply pipe, abnormal combustion may cause
E110.
●● Check the installation of the flue.
2. Check if rainwater is collected due to vertical installation of the air intake pipe.
5.1.11 407Error
Error conditions and Check Items
Error
E407
Hot water outlet
Temperature sensor
open / short
Description
If an error (open: 14°F (-10°C) or lower) in the Hot water outlet temperature sensor is detected, the system
displays the 407E error on the front panel. If this occurs, the water heater initiates shutdown.
1. Check if the Hot water outlet temperature sensor connector is wet due to any reason, including leakage.
Check items
2. Check the Resistance of the Hot water outlet temperature sensor.
3. Replace the defected Hot water outlet temperature sensor.
4. Replace the controller.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
99
5.1.12 421Error
Error conditions and Check Items
Error
E421
Heat exchanger input
temperature sensor
open
Description
If an error (open: 14°F (-10°C) or lower) in the heat exchanger input temperature sensor is detected, the system
displays the 421E error on the front panel. If this occurs, the water heater initiates shutdown.
1. Check if the heat exchanger input temperature sensor connector is wet due to any reason, including leakage.
Check items
2. Replace the defected heat exchanger input temperature sensor.
3. Replace the controller.
Is the inlet thermistor
normal?
Yes
Check connector
(#1 and #2 of CON 7)
NO
Replace inlet thermistor
Resistance between #1 and #2 of CON7 is from
0.437kΩ to 176kΩ at normal condition.
(see page 52 for Wiring Diagram)
Before measuring resistance of the thermistor,
detach the connector from the PCB.
Check method
Fault
Check method
Possible Causes
Defective temperature
sensor connector
Defective sensor
Temperature sensor
Defective PCB
Check if the temperature sensor is open and if the connector is connected properly.
Check the resistance of the temperature sensor. (Defective if it is 30kΩ or higher)
●● Replace the temperature sensor if the resistance value is abnormal.
●● Check the temperature displayed on the front panel.
If the issues continue despite checking the items above, replace the PCB.
Possible Issues
Heat exchanger input temperature sensor /
connector
100
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Check if the secondary water temperature
sensor is open
Error type : MΩ Open
Version 2.21
5.1.13 432Error
Error occurrence conditions and check items
Error
E432
Cold Water water
temperature sensor
open
Description
If an error (open: 14°F(-10°C) or lower) in the cold water temperature sensor is detected, the system displays the
432E (cleared automatically) error message on the front panel. The water heater initiates shutdown mode.
1. Check if the cold water temperature sensor is open and if the connector is attached properly.
Check items
2. Check the defect of the cold water temperature sensor.
3. Defective PCB
Is the secondary
heat exchanger inlet
thermistor normal?
Yes
Check connector
( #5 and #6 of CON 7)
(see page 52 for Wiring Diagram)
NO
Replace the secondary heat
exchanger inlet thermistor
Resistance between #5 and #6 of CON 7 is from
0.437kΩ to 176kΩ at normal conditions.
Before measuring resistance of the thermistor,
detach the connector from the PCB.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
101
Check method
Fault
Defective sensor
Possible Causes
Defective temperature
sensor connector
Temperature sensor
Defective PCB
Check method
Check if the cold water temperature sensor is open and if the connector is attached
properly.
●●
●●
Measure the temperature sensor resistance. (Defective if it is 30kΩ or higher.)
Replace the temperature sensor if the resistance is abnormal
If the issue continues despite the checking the items above replace the PCB.
Other trouble
Direct water temperature sensor
Check if the water temperature sensor is open.
Error type: MΩ Open
5.1.14 434Error
Error occurrence conditions and check items
Error
Description
E434
Water Adjustment valve
error
If the water adjustment valve does not work properly due to a defective feedback sensor, water adjustment
valve, or PCB board, the system displays 434E (cleared automatically/manually).<only when in CASCADE mode>
●● Water adjustment valve error – The system commands opening of the water adjustment valve, but the valve
remains closed. [Check the feedback sensor.] (Cleared manually)
●● If the Water adjustment valve sensor open/short-circuit is detected, the system displays an error message. If
flow is sensed, the system clears the error automatically and provides the hot water. If open/short-circuit is
detected after hot water is used, the system displays the error message.
If the 434 error occurs, connect the Water adjustment valve to the PCB. The valve must be kept open when the
water heater is not operating. If the PCB is defective, the motor keeps operating and the valve continues to make
attempts to open/close.
Check items
1. Defective water adjustment valve
2. Defective PCB
3. Check the operation of the water adjustment valve using the Component Test mode (refer to page 47).
102
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Panel Test operation mode
(WAV operation)
Is the operation normal?
Yes
Reset the unit
NO
Check connector motor resistance
(CON8)
(see page 52 for Wiring Diagram)
Check method
Fault
Possible Causes
Check method
If an error occurs in the cascade system, disconnect the cascade cable and check the
system in the following procedure:
Remote controller /
PCB error
Malfunction of water
adjustment valve
Defective water
adjustment valve
1. Check the operation of the water adjustment valve using the Component Test
mode (refer to page 47).
2. If the PCB is defective, the motor keeps operating as the water adjustment valve is
OPEN or CLOSED, or the valve repeats open/close.
3. Replace the water adjustment valve for other symptoms.
4. As a temporary measure, you can disassemble the water adjustment valve, open it
manually, and separate the power cable of the water adjustment valve.
1. Open or short-circuit of the flow control valve sensor.
Water heater works but
error occurs
Defective water
adjustment valve
sensor
2. Check the connector assembly and wiring state of the water adjustment valve
feedback sensor.
3. Check the operation of the water adjustment valve using the Component Test
mode (refer to page 47).
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
103
Emergency measures for a blocked water adjustment valve * (refer to page 47 for Component Test
mode information)
1. Switch off power, shut off water supply to the unit, and drain water from the unit.
2. Remove the top/bottom clips of the water adjustment valve.
3. Disassemble the motor and open the lid.
4. Turn the water adjustment valve axis disk counterclockwise until it does not turn anymore.
5. Pull out the water adjustment valve power connector.
6. Reconnect power and start the unit while using hot water.
Turn the gear clockwise to open the valve
manually
104
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Closed Position
Open Position
Version 2.21
5.1.15 438Error ("A" models only)
Error occurrence conditions and check items
Error
Description
Connect the power, start the pump, and check if the system senses water flow.
If flow is not sensed after the pump has started, the system displays 438E (cleared automatically) on the front
panel.
E438
Pump error
1. Defective flow sensor.
2. Defective pump.
* Check water filter for debris.
* Check for locked air in the pump.
Check items
3. Defective PCB.
* Check the operation of the pump and flow sensor using the Component Test mode (refer to page 47).
Panel Test operation mode
(PUMP operation)
Is there cold water
supply inside water
heater?
NO
Supply cold water to the water
heater.
NO
Is the pump operating
at normal voltage?
Yes
Is the circulation pump
operating normally?
Yes
Check water flow sensor
Yes
NO
Reset the unit
Check the voltage #1 and #3 of CON2: 97 - 138VAC
(see page 52 for Wiring Diagram)
Check the PUMP resistance
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
105
Check method
Fault
Possible Causes
Check method
Defective flow sensor
Check the current flow rate displayed on the front panel.
The flow sensor is defective if the water flow displayed is 0.0 gal/min when the pump is
operating or when water is discharged from the hot water tap.
Pump Malfunction
Direct water temperature sensor
1. Check if the pump is working normally.
Defective pump
2. Check the pump power cable connector and verify that the wiring is properly
installed.
3. Check the power supply to the pump (AC 102-132 V).
4. Check for air in the system.
Defective pump
Circulation pump
Other trouble
106
Defective PCB
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Circulation pump wire: Yellow-White
If the issue continues despite checking the items above, the PCB could be defective.
Replace the PCB.
Version 2.21
5.1.16 439Error
Error occurrence conditions and check items
Error
E439
Flow sensor error
Description
As one or more units are operating in the cascade system, if no flow is detected while the system opens the
water adjustment valve, the system considers it as a defective flow sensor. The system displays 439E (cleared
manually) on the front panel and switches the unit operation into the Lock-Out mode (gas valve and ignition
transformer locked).
1. Check the supply of cold water while the cascade system is disabled. (frozen/locked valve).
Check items
2. Defective flow sensor.
3. Defective PCB.
Disable cascade operation and
open faucet
Is there water flow?
NO
Check cold water supply
Yes
Check flow sensor connector (CON6)
Clean water flow sensor
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
107
Check method
Fault
Possible Causes
No hot water flow
Cold water supply
error
Check method
1. Check if the water adjustment valve is opening/closing properly.
2. Check if the cold water line is frozen.
3. Check if the cold water filter is clogged.
Water heater not
working
Defective flow sensor
1. Check the current flow displayed on the front panel.
●● If the flow sensor is defective, the displayed flow value is 0.0 while water flows
from the hot water tap.
●● Remove the flow sensor and blow into it. The rotation detector on the flow
sensor is defective if the impeller rotates and display remains 0.0.
* Component Test mode may also be used to check the operation of the flow
sensor (refer to page 47).
2. Check connector assembly and contact of the flow sensor.
3. Check the input voltage of the flow sensor.
●● Operating voltage (Black + Red) : Defective PCB if DC 12 V is not supplied.
4. Replace the flow sensor if no flow is detected while the operating voltage is
normal.
Other trouble
Defective PCB
If the issue continues despite the checking of items above the PCB is defective.
Emergency measures for a defective flow sensor
Replacement of the part is usually required for the water heater to operate when an error occurs with the flow sensor. If it is
impossible to replace the part immediately, use the following emergency measures.
If the flow sensor impeller is stuck due to foreign substances:
Remove the flow sensor and blow air through the part from the inlet side. If the impeller does not rotate, disassemble the impeller, and
remove the foreign substance before reassembling it.
If the flow displayed on the front panel is 0.0, and the impeller rotates when you blow into it, the flow sensor will need to be replaced.
108
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
1. Drain water from the unit, then remove the 4 screws and
retaining clips from the flow sensor.
3. Blow air through the flow sensor. Check that the impeller
rotates freely.
2. Detach the 2 wire connectors that connect the flow sensor to
the PCB.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
109
5.1.17 441Error
Error occurrence conditions and check items
Is the heat exchanger
outlet thermistor
operating normally?
Yes
Check connector
( #3 and #4 of CON 7)
(see page 52 for Wiring Diagram)
NO
Replace heat exchanger outlet
thermistor
Resistance between #3 and #4 of CON 7 is from
0.437kΩ to 176kΩ at normal condition.
Before measuring resistance of the thermistor,
detach the connector from the PCB.
5.1.18 445Error
Error occurrence conditions and check items
Error
Description
E445
Mixing valve error
If the mixing valve does not work properly due to a defective feedback sensor, mixing valve, or PCB board, the
system displays 445E (cleared automatically/manually).
●● Mixing valve error – The system commands opening of the mixing valve, but the valve remains closed. [Check
the feedback sensor.] (Cleared manually)
●● If a mixing valve sensor open or short-circuit is detected, the system displays an error message. If flow is
detected, the system clears the error automatically and provides hot water. If an open or short-circuit is
detected after hot water is used, the system displays the error message.
If the 445 error occurs, connect the mixing valve to the PCB. The valve must be kept open when the water heater
is not operating. If the PCB is defective, the motor keeps operating and the valve continually attempts to open or
close the valve.
Check items
1. Defective mixing valve
2. Defective PCB
3. Check the operation of the mixing valve using the Component Test mode (refer to page 47).
110
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Panel Test operation mode
(Mixing valve operation)
Is the operation normal?
Yes
Reset the unit
NO
Check connector motor resistance
(CON9)
(see page 52 for Wiring Diagram)
Check method
Fault
Possible Causes
Check method
1. Check the operation of the mixing valve using the Component Test mode (refer to
page 47).
Remote controller /
PCB error
Malfunction of mixing
valve
2. If the PCB is defective, the motor keeps operating as the mixing valve is OPEN or
CLOSED, or the valve repeats open/close.
Defective mixing valve
3. Replace the mixing valve for other symptoms.
4. As a temporary measure, you can disassemble the mixing valve, open it manually,
and separate the power cable of the mixing valve.
1. Open or short-circuit of the flow control valve sensor.
Water heater works but
error occurs
Defective mixing valve
sensor
2. Check the connector assembly and wiring state of the mixing valve feedback
sensor.
3. Check the operation of the mixing valve using the Component Test mode (refer to
page 47).
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
111
Emergency measures for a blocked mixing valve * (refer to page 47 for Component Test mode
information)
1. Switch off power, shut off water supply to the unit, and drain water from the unit.
2. Remove the top/bottom clips of the mixing valve.
3. Disassemble the motor and open the lid.
4. Turn the mixing valve axis disk counterclockwise until it does not turn anymore.
5. Pull out the mixing valve power connector.
6. Reconnect power and start the unit while using hot water.
Turn the gear clockwise to open the valve
manually
112
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Closed Position
Open Position
Version 2.21
5.1.19 515Error
Error occurrence conditions and check items
Error
Description
If an error occurs in the internal circuit of the PCB (e.g., resistance, transistor or relay fault), the system displays
515E (cleared manually) on the PCB.
E515 error
1. Defective PCB
2. Check with a multimeter if the PCB is supplied with the proper voltage (AC 102~132 V).
Check items
3. Check the wire connection.
4. Disconnect the ground wire, then check the PCB
Check the sub code
number of E515
Number 1, 2 or 10
Number 3 or 4
Check the wire connection
between gas controller and
Main PCB.
Number 9
Check the Fan voltage.
Number 11 or 12
1. Check the wire connection
between dual venturi and
Main controller.
2. Check the dual venturi.
1. Turn off and on the POWER
RESET switch.
2. In that same case, replace the
Main PCB.
Check method
Fault
Possible Causes
Defective PCB
Power supply error
PCB or Electrical supply
Power supply
grounding noise
Check method
Replace the PCB if there is an error with the PCB internal circuit.
Check with a multimeter if the PCB is supplied with the proper voltage.
●● Check with a multimeter if the voltage at the electrical outlet is AC 102~132 V.
Power supply grounding noise causes malfunction.
●● Disconnect ground from the grounding terminal inside the unit, and check if the
PCB is operating normally.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
113
5.1.20 517Error
Error occurrence conditions and check items
Are the DIP S/W on the
PCB properly set?
Yes
Reset the unit
NO
Change the DIP S/W to the
proper settings
5.1.21 593Error
Error occurrence conditions and check items
Are the panel keys
operating normally?
Yes
Reset the unit
NO
Replace front panel
114
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
5.1.22 594Error
Error occurrence conditions and check items
Error
E594 error
Check items
Description
If the communication is abnormal in parts of PCB, the system displays E594 on the PCB.
1. Check the PCB.
Check method
Fault
Possible Causes
E594 Error
Abnormal
communication by
PCB.
Check method
1. Click the Reset button on Front panel.
2. Turn the POWER to the unit OFF then ON. Disconnect then reconnect power if
necessary.
3. If the system still displays E594, replace the main PCB.
5.1.23 615Error
Error occurrence conditions and check items
Error
E615 error
Check items
Description
Abnormal signal input by PCB.
1. Turn the POWER RESET switch OFF then ON (or unplug and replug the power supply.
2. If the system still displays E615, replace the main PCB.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
115
5.1.24 736Error
Error occurrence conditions and check items
Is the Ready-Link cascade
cable properly installed
on all units?
Yes
Reset the unit
NO
Reconnect cascade wire
5.1.25 782Error
Error occurrence conditions and check items
Is the wiring from the
front panel properly
connected to the PCB?
Yes
1 step: Reset the unit.
2 step: If problem persists,
replace the PCB and Front panel.
NO
Reconnect panel to the PCB
116
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
5.1.26 740Error
Error occurrence conditions and check items
Error
E740
Abnormal outdoor
sensor
Description
If an error (under 2.2kΩ or over 122.2kΩ) in the outdoor sensor is detected continuously for 3 seconds, The
system displays the error message E740 on the front panel. If this occurs, the water heater changes the control
mode from Reset Curve Mode to Normal Mode.
1. Check if the outdoor sensor connector is wet due to any reason, including leakage.
2. Check the Resistance of the outdoor sensor.
Check items
3. Check the parameter setting. (refer to page 155)
4. Replace the defected Hot water outlet temperature sensor.
5. Replace the controller.
5.1.27 760Error
Error occurrence conditions and check items
Error
Description
E760
Flushing Alram
If the water heater operate more than set flushing time(day), The system displays the error message E760 on the
front panel. If this occurs, the water heater operate with Normal Mode.
Check items
1. Check the water heate and flushing the water heate, if it is required.
2. Reset the timer with reset button on the front panel.
5.1.28 785Error
Error occurrence conditions and check items
Error
E785
Abnormal External Flow
Switch
Description
If an AHU heating is OFF and Flow Rate is O and Flow Switch is detected continuously for 3 seconds, The system
displays the error message E785. If this occurs, the water heater operate AHU heating Mode and operate DHW
mode when the water heater detect saved flowrate plus 0.4gpm(1.5 lpm) more.
1. Check if the Flow Switch is ON or OFF.
Check items
2. Check the Resistance of the terminal block.
3. Replace the controller.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
117
5.2 Troubleshooting guide by symptom
5.2.1 Noise
Error type
Cause
Defective installation
Vibration noise
Noise at ignition
Incorrect mounting to the wall or in an improper location.
●● Check for improper installation and reinstall the unit if necessary.
Vibration caused due to defective blower.
Check the blower. If vibration is significant, replace the fan.
●● If intermittent noise occurs during operation, check the fan for debris.
●● If vibration noise occurs during operation of the product, and stops when the case
lid is removed, check the fan.
●●
Fan vibration noise
Regular noise
Check method
Defective flow sensor
Rotating noise due to debris caught in the flow sensor.
Malfunction of water
adjustment valve
Noise due to repeated opening/closing of water adjustment valve due to a defective
PCB.
Gas and air differential
pressure error
(Pop, Beep, Explosive
ignition)
1. Offset pressure adjustment error (refer to page 29)
●● Adjust offset pressure with the pressure adjusting screw on the main gas valve.
●● Set the PCB DIP 4-switch to 1-OFF,2-ON (low fire) or use the Front Panel to set the
unit at "MIN.1" (refer to page 40).
●● If noise occurs at standard value, adjust setting above/below the standard.
2. Gas supply error due to defective air pressure sensor.
3. If the same error is repeated, it is due to a defective PCB.
Boiling noise
How to check boiling:
●● Boiling occurs if the water temperature rises to149 °F ~167 °F(65 °C~75 °C).
The heat exchanger is clogged partially due to scale deposits. Flush the main heat
exchanger to remove scale.
●● Replace the heat exchanger if the error occurs from the start of the installation.
Whirring
Exhaust gas that is recirculated into the water heater through the air inlet could
produce abnormal combustion noises.
●● Check the distance between intake and exhaust (at least 12" (300mm)).
●● Check the distance between flues if two or more units are installed (at least 12"
(300mm)).
●● Check if there are any obstructions near the flue.
Noise during
combustion
1. Noise occurs due to low gas pressure.
●● Check the gas supply pressure (dynamic pressure)
Low gas pressure
(whirring)
2. Low gas supply due to offset pressure error. (refer to page 29)
●● Set the PCB DIP 4-switch to 1-OFF,2-ON (low fire) or use the Front Panel to set the
unit at "MIN.1" (refer to page 40).
Noise due to defective air pressure sensor.
●● Replace the air pressure sensor.
Noise during
combustion
118
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
●●
●●
Noise due to damaged air pressure hose.
Noise may be intermittent depending on the size of the damage.
Version 2.21
5.2.2 Water Temperature Issue
Error type
Cause
Front panel power off
Hot water does not run if the front panel is switched off.
Defective flow sensor
The water heater does not work due to the defective flow sensor.
●● The flow sensor impeller will not rotate if it contains excessive scale or debris. Clean
out the flow sensor if possible.
●● If the impeller rotates normally, replace the flow sensor back into the water heater.
●● The sensor may be reused temporarily after cleaning, but replacement is
recommended.
Defective hot water
temperature sensor
The temperature is sensed higher than the actual temperature due to a defective hot
water (cold water) sensor.
●● Hot water temperature is low although hot water is recognized by the water heater.
●● The cold water temperature sensor may not work be working properly.
Water heater is not
operating properly.
Low hot water
temperature
Check method
Hot water setting error
Check the hot water temperature setting on the front panel.
Water mixed with cold
water.
The temperature of hot water at the tap is low while the temperature is high at the hot
water outlet.
●● Cold water and hot water are mixed due to improper pipe installation.
●● Cold water and hot water are mixed due to improper piping at the hot water faucet.
1. The cold water valve is closed.
2. Check if the cold water filter is clogged with foreign substance.
No hot water from the
valve
Check the pipe
3. The water adjustment valve is closed. (Refer to E434 on page 102)
4. Check if the cold water / hot water pipes are frozen during the winter.
5. The main heat exchanger is clogged (by scale).
6. Low inlet water pressure
Cold water flows
temporally
Pre-heating does not
work
For the A model, the system initiates the internal/external circulation preheating when
a recirculation mode is selected on the front panel DIP switches. Confirm the DIP
switch settings.
Troubleshooting
Downloaded from www.Manualslib.com manuals search engine
119
5.2.3 Circuit breaker operation
Error type
Cause
Check method
Power supply
The circuit breaker trips immediately as soon as the power cord is plugged in the
receptacle.
Check the sheath of power cord, or if there is short-circuit.
Check the components in order from the power transformer to the PCB.
Defective part
assembly
If the circuit breaker operates after repairs check the wiring of each part.
Maintain proper direction when assembling the ignition transformer.
Be careful that wire is not compressed when assembling the main gas valve
Check if the wire is fixed and properly attached on the main side of the heat exchanger.
Circuit breaker trips
Normal assembly
Short-circuit due to defective assembly
Circuit breaker
operates while
the water heater is
running
Remote controller
power
120
Check the wire
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Wiring near the heat exchanger
If circuit breaker trips during the operation of the water heater, check the order of
operation, and replace the concerned part.
e.g., The circuit breaker operates at switchover to burner stage 2 after ignition.
► Replace the dual venturi.
Check the power supply to the remote controller terminal. (DC 19 V or higher).
If there is a problem in power supply, check the output voltage of the PCB, and take the
action separately for wiring error and defective PCB, respectively.
If the power supply is normal, replace the remote controller.
Version 2.21
6. Replacement of Parts
6.1 Replacement Procedure
6.2 Components Replacement
Instructions
CAUTION
1. When performing maintenance and/or servicing the
water heater, always turn off the electric power, gas and
water shut-off valve. Wait for the water heater to become
cool. Be careful to avoid injury to your fingers on sharp
edges.
2. Drain all water from the water heater when removing the
waterway components.
3. Before any disassembly, make sure that all issues and error
codes are properly diagnosed.
6.2.1 PCB
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the screws that are located near the top and bottom
of the PCB that hold it in place as shown in Figure 1.
4. Handle all parts carefully.
5. When reassembling, prevent any foreign substance, i.e.
dust, etc. from entering back into the water heater.
6. After reassembling, check for gas and water leakage.
Then, test for proper ignition. Make sure that there is no
gas leakage from the gas connections by testing with
soap bubble solution. Bubbles indicate a gas leak that
must be corrected.
7. Check the performance and operation after the water
heater has been serviced.
To remove and replace any parts from the water heater, you will
need a screwdriver that is at least 8 ~ 10 inches long. A flashlight
and magnetic tip are also recommended. Navien recommends
the use of a parts tray to hold small parts and screws. All of the
hardware is essential to the proper operation of the unit upon
re-assembly.
Figure 1
5. Disconnect all wiring connectors from the PCB as shown in
Figure 2.
NOTE
When disassembling and reassembling the water heater, refer
the components diagram & parts list.
Figure 2
6. Remove the 2 screws located on the back of the case.
Replacement of Parts 121
Downloaded from www.Manualslib.com manuals search engine
7. Remove the old PCB and replace it with the new part.
4. Replace the old fuse with the new part.
8. Reattach all wiring connectors to the PCB.
5. Ensure that the new fuse is of an equivalent rating and that it is
properly fixed inside the housing.
9. Set the proper DIP S/W settings on the PCB (refer to page
90).
10. Reinstall the PCB using the 2 screws previously removed.
11. Turn on the water and gas supplies, then reconnect the power
supply to the unit.
NOTE
6. Close the fuse housing.
7. Turn on water supply, power supply, and gas supply to the
unit.
6.2.3 Fan Motor (Combustion Air)
1. Turn off the gas supply to the unit.
All wiring harness connections to the PCB should match in
color and pintypes. Do not use excessive force when removing
the connectors as this may cause damage to the PCB.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the mounting screw from the fan assembly as shown
in Figure 4 below.
6.2.2 Fuse
5. Remove the fan assembly bracket with the attached intake
port.
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Locate the fuse housing shown in Figure 3 below. Open the
housing to expose the fuse.
Figure 4
Figure 3
122
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
6. Disconnect the wiring connector from the fan assembly, and
then remove the 4 screws from the gas valve connection as
shown in Figure 5 below.
12. Reinstall the fan assembly to the bracket by using the
mounting screw.
13. Attach the gas valve connection back to the fan assembly by
using the 4 screws as shown in Figure 5.
14. Reconnect the wiring connector from the fan assembly.
15. Turn on water supply, power supply, and gas supply to the
unit.
NOTE
Do not over-tighten the screws for the fan motor replacement
with high torque drill. This may cause damage to the part(s).
Figure 5
7. Pull out the fan assembly and remove the 4 screws that secure
the air intake port to the fan assembly.
8. Remove the four screws from the bottom of the fan assembly.
6.2.4 Flame Rod
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the Ignition Transformer insulated cables.
5. Remove the 2 screws from the flame rod as shown in Figure 7
below.
Figure 6
9. Detach the fan motor from the assembly and replace it with
the new part.
10. Replace the 4 screws used to attach the fan motor to the
assembly.
Figure 7
11. Remove procedure of gas pipe from gas valve.
Replacement of Parts 123
Downloaded from www.Manualslib.com manuals search engine
6. Remove the flame rod wiring connector.
5. Disconnect the wiring connector from the Ignition Transformer
(Figure 9).
Figure 8
7. Remove the flame rod from the burner assembly and replace
with the new part.
8. Reconnect the 2 ignition transformer insulated cables to the
new flame rod.
Figure 9
6. Remove the 2 screws from the Ignitor Transformer.
9. Place the new flame rod back onto the burner assembly and
secure it by using the 2 screws from Figure 7.
10. Turn on water supply, power supply, and gas supply to the
unit.
NOTE
Always use new factory gaskets included with the flame rod
when replacing the part onto the burner assembly.
Figure 10
6.2.5 Ignition Transformer
1. Turn off the gas supply to the unit.
7. Pull out the Ignition Transformer.
2. Disconnect the unit from the power supply.
8. Replace the old Ignition Transformer with the new part, and
then use the 2 screws to secure the part.
3. Turn off the water supply to the unit.
4. Remove the Ignition Transformer insulated cables from the
flame rod.
9. Reconnect the Ignition Transformer insulated cables to the
flame rod.
10. Reattach the wiring connectors from the Ignition Transformer.
11. Place the front panel back onto the unit and secure it by using
the 4 screws.
12. Turn on water supply, power supply, and gas supply to the
unit.
NOTE
Verify that the Ignition Transformer insulated cables are firmly
connected to the flame rod.
124
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
6.2.6 APS
6. Remove the 2 screws that attaches the air pressure sensor to
the burner assembly.
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the air pressure sensor wiring connector (Figure 11).
7. Pull out the air pressure sensor.
8. Replace the old air pressure sensor with the new part.
9. Reattach the air pressure sensor hose.
10. Connect the air pressure sensor wiring connector.
11. Place the front panel back onto the unit and secure it using the
4 screws.
12. Turn on water supply, power supply, and gas supply to the
unit.
NOTE
Confirm that the new air pressure sensor is in the proper
position before turning the unit back on.
Figure 11
5. Remove the hose from the air pressure sensor.
6.2.7 Main Gas Valve
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the 2 screws.
5. Disconnect the wiring connector at the gas valve.
Figure 12
Figure 13
Replacement of Parts 125
Downloaded from www.Manualslib.com manuals search engine
6. Remove the 4 screws located at the bottom of the unit that are
attached to the gas valve.
Figure 15
8. Remove the 4 screws directly from the bottom of the gas valve
to remove the elbow.
7. Remove the 4 screws directly on the bottom of the gas valve to
remove the gas pipe.
9. Replace the O-ring where the gas valve assembly attaches to
the elbow. Make sure the old O-ring is discarded.
10. Replace the old gas valve with the new part and reattach the
elbow and gas pipe to the gas valve.
11. Reconnect the gas valve assembly to the unit by using the
4 screws at the elbow and 2 screws at the gas pipe.
12. Reattach the gas valve wiring connector.
WARNING
Failure to correctly assemble the components according to
these in-structions may result in a gas leak or explosion.
13. Check that all gas connections are tightly sealed to ensure that
no gas leaks are present.
14. Turn on water supply, power supply, and gas supply to the
unit.
Figure 14
15. Verify the gas pressures to the unit with the values provided in
this Service Manual.
NOTE
Always replace the old O-rings and gaskets with new parts
to ensure tight seals between connections. Ensure that all
properly sized O-rings are used for the replacement.
126
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
6.2.8 Condensate Trap
7. Loosen the clip that secures the hose to the condensate trap,
and then pull off the hose.
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the pin that secures the condensate drain cap and
then remove the cap. Use a bucket to collect the condensate.
Figure 18
Figure 16
8. Remove the old condensation trap and replace it with the new
part.
5. Detach the condensate piping from the unit.
9. Reconnect the hose to the condensate trap.
6. Remove the 3 screws located at the bottom of the unit that are
attached to the condensate trap.
10. Reattach the condensation trap to the unit and secure it using
the 5 screws.
11. Replace the controller to its original position.
12. Turn on the water supply, power supply, and gas supply to the
unit.
NOTE
Ensure that the condensate drain trap is completely inserted
into the condensate fitting to eliminate leaking. Use the pin to
secure the cap to the fitting.
Figure 17
Replacement of Parts 127
Downloaded from www.Manualslib.com manuals search engine
6.2.9 Flow Sensor
6. Pull out the flow sensor.
1. Turn off the gas supply to the unit.
7. Replace with old flow sensor with the new part.
2. Disconnect the unit from the power supply.
8. Reinstall the flow sensor into the cold water inlet pipe and
reattach the stainless clip. Ensure that the flow sensor is
properly connected to the cold water inlet pipe and that the
clip is tightly holding the two parts together.
3. Turn off the water supply to the unit. Drain all water from the
appliance.
4. Remove the stainless clip and four screws at the flow sensor.
9. Reinstall the four screws at the flow sensor to secure the part
to the heat exchanger.
10. Turn on water supply, power supply, and gas supply to the
unit.
11. Carefully open a hot water tap and ensure there are no leaks at
the flow sensor connections.
6.2.10 Buffer Tank
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
Figure 19
5. Detach the 2 wire connectors that connect the flow sensor to
the PCB.
3. Turn off the water supply to the unit. Drain all water from the
appliance.
4. Remove the gas valve to gain access to the buffer tank (refer to
the gas valve replacement procedures).
Figure 21
Figure 20
128
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
5. Remove the clip at the bottom of the buffer tank.
11. Turn on water supply, power supply, and gas supply to the
unit.
12. Carefully open a hot water tap and ensure there are no leaks at
the buffer tank connections.
NOTE
1. Use caution when removing the buffer tank from the unit
as it may contain scalding hot water.
2. Use properly sized O-rings at the buffer tank connections.
3. Protect the electrical components as contact with excess
water could cause damage.
Figure 22
6. Remove the 3 mounting screws from the buffer tank.
6.2.11 Circulation Pump
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit. Drain all water from the
appliance.
4. Remove the 3 screws from the bottom of the case along with
the screw that connects the rear bracket to the case in order to
detach the front panel from the unit.
Figure 23
Figure 24
7. Pull out the buffer tank.
8. Replace the old buffer tank with the new part.
9. Reinstall the buffer tank by using the 4 mounting screws.
10. Attach the gas valve assembly back onto the unit (refer to the
gas valve replacement procedures).
Replacement of Parts 129
Downloaded from www.Manualslib.com manuals search engine
5. Move the controller aside for better access to the Circulation
Pump.
9. Disconnect the wiring connector at the pump assembly.
6. Remove the 2 screws from the bottom of the case.
Figure 27
Figure 25
10. Carefully remove the pump.
7. Unscrew the pump drain plug.
8. Remove the stainless steel clip and 2 screws from the pump as
shown in Figure 26.
Figure 28
11. Replace with the new pump.
Figure 26
12. Place the new pump back into its original position and ensure
that all connections are tightly sealed.
13. Secure the pump with the stainless steel clip and the 2 fixing
screws.
14. Reinstall the pump drain plug at the bottom of the unit.
15. Reconnect the wiring connector at the pump.
16. Attach the controller back onto the unit by using the 3 screws
at the bottom of the unit.
17. Fix the pump bracket to the case with the mounting screw.
130
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
18. Use the 4 screws at the bottom of the case to fix the pump to
the unit.
5. Remove the 4 stainless steel clips from the connections (2
round clips and 2 flat clips).
19. Install front panel using 4 screws.
20. Turn on water supply, power supply, and gas supply to the
unit.
21. Open a hot water tap and ensure that there are no leaks at the
pump connections.
22. Open the air vent on top of pump to release air within the
system.
NOTE
Always use proper O-rings at the pump connection to ensure
tight seals
Figure 30
6.2.12 2-Way Valve
6. Disconnect the wiring connector at the 2-way valve.
1. Turn off the gas supply to the unit.
2. Turn off the 120V power supply to the unit.
3. Turn off the water supply to the unit. Drain all water from the
appliance.
4. Remove the 3 screws at the hot water outlet fitting to loosen
the 2-way valve that is attached to the hot water outlet fitting.
Figure 31
Figure 29
Replacement of Parts 131
Downloaded from www.Manualslib.com manuals search engine
7. Remove the 3 buffer tank screws and pull out the buffer tank
Figure 33
5. Remove the 2 stainless steel clips from the water adjustment
valve connections.
Figure 32
8. Replace with new 2-way valve.
9. Place the 2 round stainless steel clips and 2 flat stainless clips
back onto the 2-way valve connections.
10. Replace the 4 buffer tank mounting screws.
11. Reconnect the wiring connector at the 2-way valve.
12. Place the front panel back onto the unit using 4 screws.
13. Turn on water supply, power supply, and gas supply to the
unit.
14. Open a hot water tap and ensure there are no leaks at the
water heater.
Figure 34
6. Remove the water adjustment valve.
7. Replace with the new water adjustment valve.
6.2.13 Water Adjustment Valve
8. Place the 2 stainless steel clips back onto the valve
connections. Ensure that the clips are securely holding the
connection together to prevent leaks.
1. Turn off the gas supply to the unit.
9. Reattach the water adjustment valve wire connectors.
2. Disconnect the unit from the power supply.
10. Turn on water supply, power supply, and gas supply to the
unit.
3. Turn off the water supply to the unit. Drain all water from the
appliance.
11. Open a hot water tap and ensure there are no leaks at water
adjustment valve connections.
4. Disconnect the mixing valve wire connector.
132
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
7. Components Diagram and Part List
7.1 Case Assembly
12
1
11
2
4
3
6
7
17
16
15
14
5
18
13
10
9
8
Components Diagram and Part List 133
Downloaded from www.Manualslib.com manuals search engine
134
#
Description
Part #
1
Intake Air Duct Assembly
30008662B
2
Intake Air Filter
20007667A
3
Case
4
Air Pressure Sensor
30010346A
5
Panel Bracket
20018388A
6
Cover
7
Case Lower Bracket
20007643B
8
PCB
30011690D
9
Power Switch
30009482A
10
Front Panel
30008333A
11
Case Bracket
20007609A
12
Exhaust Pipe Assembly
30008673A
13
Rubber Ring
20025127A
14
Saddle
20013508A
NPE-150S/180S/210S/240S
15
Saddle Bracket 1
20026170A
NPE-150S/180S/210S/240S
16
Freeze Protector Sensor
30002587A
NPE-150S/180S/210S/240S
17
Freeze Protector Sensor Bracket
20007671A
NPE-150S/180S/210S/240S
18
Saddle Bracket 2
20026172A
NPE-150S/180S/210S/240S
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Remark
20019078C
NPE-180A/210A/240A
20026559B
NPE-150S/180S/210S/240S
30008678B
NPE-180A/210A/240A
30011694A
NPE-150S/180S/210S/240S
Version 2.21
7.2 Burner Assembly(NPE-180A/ 210A/ 240A)
6
18
13
3
5
7
2
19 20
14
7-1
6-1
10
8
12
19
14
20
12
6-1
9
1
19
12
12
11
21
15
6-1
6-1
4-1
17-1
17
11-1
4
19
21
6-1
12
17
6-1
12
6
Components Diagram and Part List 135
Downloaded from www.Manualslib.com manuals search engine
#
1
Heat Exchanger Assembly
Part #
Remark
30012711A
NPE-180A
30012712A
NPE-210A
30012713A
NPE-240A
2
Fan O-Ring (G50)
20003019A
3
Fan Bracket(F)
20022095A
4
Flow Sensor Assembly
30008571A
Thermistor
30008366A
Fan Braket(R)
20022096A
4-1
5
6
6-1
7
7-1
8
9
Cold Inlet Pipe
30009166A
NPE-180A
30010805A
NPE-210A
30008446A
NPE-240A
O-Ring (Φ17.5x2.7t)
20006947A
WPA-A (Clip)
20018344A
Thermistor
30008366A
WPA-B
20018343A
H-Ex Middle Pipe
30009126A
NPE-180A
30010803A
NPE-210A
30008439A
NPE-240A
30009145A
NPE-180A
30008442A
NPE-210A/240A
10
Hot Water Outlet Pipe
11
WPA-A (Screw)
30008569A
Thermistor
30008366A
12
Fastner
20017726A
13
Ignition Transformer
30010455A
14
Fastner
20007853A
15
Ignitor
30012226A
16
Damper
30008825A
17
Buffer Tank Inlet Adapter
20018346A
O-Ring (P16)
20017210A
18
Thermistor
30009478A
19
O-Ring (Φ17.5x2.7t)
20006947A
20
Backup Ring
20018744B
21
Packing (Φ26.5x2.4t)
20006868A
11-1
17-1
136
Description
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
7.3 Burner Assembly(NPE-150S/ 180S/ 210S/ 240S)
13
1
12
2
18
17
3
10
15
14
9
20
10
4
10
21
10
7
10
17
9
10
5
10 6
22
19
16
9
24
10 15
9
23
10
6
10
8
9
10
11
25
Components Diagram and Part List 137
Downloaded from www.Manualslib.com manuals search engine
#
Description
Part #
1
Ignition Transformer
30010455A
2
Fan Bracket (R )
20022096A
3
Thermistor
30009478A
Exhaust
30015922A
NPE-150S
30012711A
NPE-180S
30012712A
NPE-210S
30012713A
NPE-240S
30214183A
NPE-150S
30012226A
NPE-180S/210S/240S
4
5
Ignitor
6
Packing (Φ26.5x2.4t)
20006868A
30014326A
NPE-150S
30011519A
NPE-180S
30011515A
NPE-210S/240S
7
Heat Exchanger Outlet Pipe
8
WPA-C (Screw)
20026780A
9
Fastner
20017726A
10
O-Ring (Φ17.5x2.7t)
11
12
Cold Inlet Pipe
Fan Damper
20006947A
30214751A
NPE-150S
30011521A
NPE-180S
30011665A
NPE-210S
30011517A
NPE-240S
30008825A
13
Fan Packing
20022744A
14
Fan Bracket (F)
20022095A
15
Backup Ring
20018744B
16
High Limit Switch
30002577A
17
Fastner
20007853A
18
WPA-A (Clip)
20018344A
19
Thermistor
30008366A
Water
20033191A
NPE-150S
20018343A
NPE-180S/210S/240S
30014330A
NPE-150S
30009126A
NPE-180S/180A
30010803A
NPE-210S/210A
30008439A
NPE-240S/240A
20
WPA-B
21
H-Ex Middle Pipe
22
WPA-A (Screw)
23
138
Heat Exchanger Assembly
Remark
Mixing Pipe
24
WPA-T
25
Hot Water Outlet Pipe
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
30008569A
30014327A
NPE-150S
30011518A
NPE-180S
30011514A
NPE-210S/240S
20025960A
30014328A
NPE-150S
30011520A
NPE-180S
30011516A
NPE-210S/240S
Version 2.21
7.4 Waterway Assembly(NPE-150S/ 180S/ 210S/ 240S)
8-3
8-4
15
8
16
8-2
1
3
17
8-1
11
3-5
2-4
12
7
10
5
3-3
13
2
2-4
14
5
4-3
2-2
2-1
11
4
7-1
9-3
6
9
9-1
2-5
2-3
11
3-4
3-1
4-1
9-3
9-2
3-2
11
12
12-5
4-2
12-4
12-2
12-3
12-1
#
Description
Part #
1
Buffer Tank
30009030A
2
Hot Water Outlet Pipe Assembly
30008338A
2-1
Pipe Adapter
20024496A
2-2
O-RING (P20)
20017212A
2-3
Thermistor (Red)
30008366A
2-4
O-RING (P16)
20017210A
2-5
Pipe Clip
20007733B
Return Pipe Assembly
30008350A
Pipe adapter
20024496A
3
3-1
Remark
Components Diagram and Part List 139
Downloaded from www.Manualslib.com manuals search engine
#
Description
Part #
3-2
O-RING (P20)
20017212A
3-3
O-RING (P19)
20017211A
3-4
Water Filter
30008171A
3-5
Pipe Clip
20007733B
Circulation Pump
30010780A
4-1
Pump Air Seperator
30006831B
4-2
Drain Plug
30008630A
4-3
O-RING (P18)
20006947A
5
Fastner
20017726A
6
Water adjustment valve (WAV)
30008245A
7
WAV Outlet Pipe Assembly
30008624A
O-Ring (P16)
20017210A
Syphon
30009756B
8-1
O-Ring (Φ31.7x3.5t)
20018013A
8-2
Syphon Clip
20018155A
8-3
Hose Clip
20007833A
8-4
Syphon Hose
20018429A
Pump Outlet Pipe Assembly
30008361A
9-1
Check Valve
30008359A
9-2
Pipe Clip
20017722A
9-3
O-Ring (P16)
20017210A
10
Return Pipe clip
20017767A
11
Fastner
20007859A
12
Cold Water Inlet Pipe Assembly
30009437A
12-1
Water Filter
30008171A
12-2
O-RING (P19)
20017211A
12-3
Pipe adapter
20024496A
12-4
O-RING (P20)
20017212A
12-5
Pipe Clip
20007733B
13
O-RING (P29)
20017923A
14
Buffer Tank adapter
20017757A
15
Buffer tank pipe A
20017759A
16
Buffer tank pipe B
20017760A
17
Fastner
20017724A
4
7-1
8
9
140
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Remark
Version 2.21
7.5 Waterway Assembly(NPE-150S/ 180S/ 210S/ 240S)
11
10
8
6
8
12
9
15
14
8
11
11
10
6
17
2
11
6
12
7
6
8
5
6
4
13
16
3
2
1
Components Diagram and Part List 141
Downloaded from www.Manualslib.com manuals search engine
142
#
Description
Part #
1
Bracket
20026489A
2
Thermistor
30008366A
3
Water Filter
30008171A
4
Cold Water Inlet Adapter
30011597A
5
O-Ring (P15)
20017217A
6
Fastner
20007859A
7
Flow Sensor
30011534A
8
O-Ring (P16)
20017210A
9
Flow Sensor Outlet Adapter
20025959A
10
Outlet Adapter
20025961A
11
Fastner
20017726A
12
Water Adjustment Valve (WAV)
30011532A
13
Inlet Adapter
20025962A
14
O-Ring (P18)
20006947A
15
How Water Outlet Adapter
30011601A
16
Siphon
30009756B
17
Siphon Hose
20018429A
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Remark
Version 2.21
7.6 Fan(Gas) Assembly
6
9
15
9
1
9
10
9
12
11
9
2
9
7
9
3
9
14
9
13
9
10
9
4
9
10
9
9
8
9
5
9
[NPE-180S/180A/210S/210A/240S/240A]
6
12
11
10
2
3
7
14
10
13
16
4
10
8
5
[NPE-150S]
Components Diagram and Part List 143
Downloaded from www.Manualslib.com manuals search engine
#
Description
1
Gas Adapter
2
Gas Pipe
Remark
30009921A
NPE-180S/180A
30009922A
NPE-210S/210A/240S/240A
30014329A
NPE-150S
30013323A
NPE180S/180A
30008431A
NPE-210S/210A/240S/240A
3
Gas Connector
20018430A
4
Gas Valve
30008429A
5
Gas Inlet Adapter
20023809A
6
Fan Assembly
Single Venturi
7
8
Dual Venturi
Silence
30015421A
NPE-150S
30008834A
NPE-180S/180A/210S/210A/240S/240A
30014688A
NPE-150S
30012770A
NPE-180S/180A
30008909A
NPE-210S/210A/240S/240A
30015322A
NPE-150S
20019142A
NPE-180S/180A
20023829A
NPE-210S/210A/240S/240A
20023861A
NPE-180S/180A
20019141A
NPE-210S/210A/240S/240A
9
Silence Adapter
10
O-Ring (P20)
20006934A
O-Ring (G70)
20007001A
NPE-150S
O-Ring (G75)
20018079A
NPE-180S/180A/210S/210A/240S/240A
Fan Packing
20022744A
11
12
13
144
Part #
Gas Orifice
20029420B
NPE-150S (NG)
20034178A
NPE-150S (LP)
20024159A
NPE-180S/180A (NG)
20024190A
NPE-180S/180A (LP)
20019144A
NPE-210S/210A/240S/240A (NG)
20024189A
NPE-210S/210A/240S/240A (LP)
20030893A
NPE-150S
14
Venturi Packing
20022660A
NPE-180S/180A/210S/210A/240S/240A
15
O-Ring (P34)
20019090A
NPE-180S/180A/210S/210A/240S/240A
16
Silence Packing
20032129A
NPE-150S
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
8. Inspection and Maintenance Schedule
8.1 Maintenance
3. Close the gas valve.
This section describes various maintenance procedures that may
need to be performed on the water heater from time to time.
8.1.1 Cleaning the Water Heater
CAUTION
Make sure the water heater is turned off and the power supply
is disconnected before cleaning the water heater. The water
heater may remain hot for several minutes after it is turned off.
To prevent burns, wait until the water heater has cooled down
before cleaning.
To clean the water heater, wipe the outside with a damp cloth. Use
a non-acidic, non-abrasive cleaner to remove any surface stains.
The front panel is moisture resistant, but it is not waterproof. Keep
it as dry as possible.
Close
4. Close the water supply valve on the inlet to the water heater. If
there is no valve, turn off the water supply at the water main.
8.1.2 Draining the Water Heater
You need to drain the water heater before performing
maintenance tasks, such as cleaning the inlet water filter, or to
prevent the water heater from freezing when it will not be used for
an extended period.
To drain the water heater:
1. Place a bucket under the water heater, to collect the residual
water inside the water heater.
2. Press the Power button on the front panel to turn off the
power to the water heater.
5. Open all hot water faucets completely. The water that remains
in the plumbing lines will drain out.
Inspection and Maintenance Schedule 145
Downloaded from www.Manualslib.com manuals search engine
6. Remove the pump inlet filter from the bottom of the water
heater.
Draining the water in the condensate trap
Referring to the below figures, place a bucket under the water
heater and remove the cap from the bottom of the trap to drain
collected condensate.
1
Cold Water
Inlet Filter
Pump Inlet Filter
23456
#
Description
1
Remove the retaining clip.
2
Place a bucket under the water heater.
3
Twist and remove the cap.
4
Clean out the condensate trap.
7. Open the pump drain plug.
5
Replace the cap and the retaining clip.
8. Remove the cold water inlet filter.
6
Pour water down the exhaust flue (if possible) or
allow the unit to run to refill the condensate trap.
Pump Drain Plug
9. Allow the residual water to drain from the water heater.
10. When the water is completely drained, reinsert the pump inlet
filter and the cold water inlet filter, and then close the pump
drain plug.
11. To refill the water heater follow the steps of “Draining the
Water Heater” in reverse.
146
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
8.1.3 Flushing the Heat Exchanger
1. Press the Power button on the front panel to turn off the water
heater.
2. Disconnect the power supply to the water heater.
CAUTION
Flushing the Heat Exchanger shall be performed only by
an authorized technician or licensed professional. Read
the following instructions carefully before attempting this
procedure. Keep in mind that improper maintenance can void
your warranty.
Before flushing the Heat Exchanger, gather the following items:
●●
●●
●●
●●
5. Connect one of the tubes to the circulation pump outlet and
the cold water line at the “B” valve.
6. Connect one tube to the circulation pump inlet and place the
free end in the bucket.
8. Open both “A” and “B” valves.
9. Turn on the circulation pump and allow the solution to
circulate through the water heater for at least 45 minutes.
To flush the Heat Exchanger:
10. Rinse the cleaning solution from the water heater:
a. Remove the free end of the drain tube from the bucket and
place it in the condensate drain or laundry tub (wherever the
water heater drains).
b. Close the “B” valve and open the “D” valve. Do not open the
“C” valve yet.
c. Allow water to flow through the water heater for 5 minutes.
d. Close the “A” valve and open the “C” valve.
11. Disconnect all tubes.
B
A
C
Navien Plumb
Easy Valve Kit
B
C
4. Connect one tube to the “A” valve and place the free end in the
bucket.
7. Pour the cleaning solution into the bucket.
A bucket that is 5 gallons or larger
Cleaning solution diluted with water
3 hoses
A submersible circulation
A
3. Close the “C” and “D” valves on the hot and cold water lines.
D
12. Remove the cold water inlet filter from the water heater and
clean out any residue.
13. Reinsert the filter and ensure the filter cap is securely
tightened.
14. Reconnect the power supply to the Water Heater.
D
Hot Water Line
Cold Water Line
15. Press the Power button on the front panel to turn on the water
heater.
Circulation Pump
Flushing Kit
Inspection and Maintenance Schedule 147
Downloaded from www.Manualslib.com manuals search engine
8.1.4 Cleaning the Inlet Water Filter and
Recirculation Inlet Filter
8.1.5 Cleaning the Air Intake Filter
1. Drain the water heater.
If the air intake filter becomes clogged by dust or lint, the water
heater will cease to operate and “Error Code 10” will appear on
the front panel display. To properly maintain the water heater, you
should clean the air intake filter every 3-4 months.
2. While the filters are removed, rinse it with clean running water
(cold) and, if necessary, scrub it clean with a brush.
To clean the air intake filter:
To clean the filters:
Cold Water
Inlet Filter
1. Press the Power button on the front panel to turn off the water
heater.
Recirculation
Inlet Filter
3. Reinsert and tighten the filters.
2. Disconnect the power supply to the water heater.
3. Remove the front cover of the water heater.
4. Remove the screw that secures the air intake filter (the filter is
located at the top left of the water heater).
4. Refill the water heater.
148
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
5. Pull the filter out of the water heater.
8.2 Annual Servicing
In order to maintain its safe and efficient operation, it is
recommended that the water heater is serviced annually.
CAUTION
Servicing must be performed by a qualified service agency or
gas supplier
Inspection
6. Remove the filter from the plastic assembly and clean it with a
toothbrush and clean running water.
●●
●●
●●
●●
●●
●●
●●
●●
●●
7. Allow the filter to dry completely.
8. Reinsert the filter into the plastic assembly.
9. Place the filter assembly back into the water heater and secure
it with the screw.
10. Replace the front cover.
Visual inspection for general signs of corrosion
Checking and adjusting the gas/air ratio
Checking Flue Gas
Carrying Out a Water Leak Test in Operation
Carrying out a gas leak test in operation
Checking Hot Water Temperature and Flow
Checking Noise
Checking venting systems
Checking the remote controller
Maintenance
●●
●●
●●
●●
●●
Draining the water heater and cleaning the inlet water filter
Cleaning the Return Filter
Cleaning the intake air filter
Flushing the heat exchanger
Replacement of parts
11. Reconnect the power supply to the water heater.
12. Press the Power button on the front panel to turn on the water
heater.
Inspection and Maintenance Schedule 149
Downloaded from www.Manualslib.com manuals search engine
8.3 Inspection Report
Inspection Items
References
Visual Inspection for General
Signs of Corrosion
YES / NO
Checking and Adjusting the
Gas/Air Ratio
YES / NO
Checking Flue Gas
YES / NO
Carrying Out a Water Leak
Test in Operation
YES / NO
Carrying Out a Gas Leak Test
in Operation
YES / NO
Checking Hot Water
Temperature and Flow
YES / NO
Checking Noise
YES / NO
Checking Venting Systems
YES / NO
Checking the front panel.
YES / NO
Date:
Date:
Date:
Date:
8.4 Maintenance Report
Inspection Items
References
Draining the Water Heater
and Cleaning the Inlet Water
Filter
YES / NO
Cleaning the Return Filter
YES / NO
Checking the Intake Air Filter
YES / NO
Flushing the Heat Exchanger
YES / NO
Replacement of Parts
150
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
9. Common Vent and Outdoor vent Cover Installing
9.1 Installing the Outdoor vent Cover
This kit must be installed by a qualified installer in accordance with
these instructions and all applicable codes and requirements of
the authorities having jurisdiction.
Keep this manual near the water heater for future reference
whenever maintenance or service is required. The following safety
symbols are used in this manual.
WARNING
●●
The outdoor vent cover gets hot during operation. Install
the heater in a location where the top of the vent cover kit
cannot be reached by children and pets.
●●
Exhaust gas will be released through the outdoor vent
cover kit. Exhaust gas is hot and contains carbon monoxide.
The outdoor vent cover kit cannot be installed on a water
heater mounted indoors. To prevent risk of fire and carbon
monoxide poisoning, observe all clearances required in this
manual.
●●
Do not place or store any combustible material within
5 feet of the appliance. Maintain specified clearance to
combustibles on the wall where the appliance is installed
and any adjacent walls or overhang. Observe all clearances
required in this manual.
●●
The water in this appliance is cold and always remains cold
except for the times when the burner is on. To prevent any
damages from freezing, always drain the water heater.
●●
Damage to the water heater from freezing is not covered
under the manufacturer's warranty.
Read and follow all safety instructions in this manual precisely
to avoid unsafe operating conditions, fire, explosion, property
damage, personal injury, or death.
DANGER
Indicates an imminently hazardous situation which, if not
avoided, could result in severe injury or death.
WARNING
Indicates a potentially hazardous situation which, if not
avoided, could result in injury or death.
Required Tool
CAUTION
Indicates a potentially hazardous situation that, if not avoided,
could result in property damage.
DANGER
If the information in these instructions is not followed exactly,
a fire or explosion may result, causing property damage,
personal injury, or death.
●●
Installation and service must be performed by a qualified
installer, service agency or the gas supplier.
●●
The installation must conform with local codes or, in the
absence of local codes, the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 and/or CSA B149.1, Natural Gas and
Propane Installation Code.
Phillips Screwdriver
Included Items
Outdoor Vent Cover
Installation Manual
Installation the Outdoor Vent Cover
Downloaded from www.Manualslib.com manuals search engine
151
9.2 Installing Procedure
3. Tighten the screws on the front of the water heater.
1. Remove the two Phillips screws on the top front of water
heater.
2. Position the outdoor vent cover on top of the water heater
and securely press it into the intake and exhaust collars as
illustrated.
WARNING
Make sure the front cover of the water heater is securely
reattached to prevent any damages to the water heater.
NOTE
Once the outdoor vent cover is installed, it does not need to be
removed before removing the front cover of the water heater.
Make sure all the screw holes are aligned, and connectors for
both vents are connected into place.
152
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
9.3 Choosing an Installation Location
When choosing an installation location, you must ensure that
the location provides adequate clearance for the water heater,
adequate venting and drainage options, and sufficient access to
gas, water, and electrical supplies. Before proceeding, read the
water heater installation manual.
●●
●●
Choose an outside wall for the installation. Installation on a wall
protected by an overhang above is recommended.
Size the water and gas connections according to the instructions
in the water heater installation manual. Use unions when
connecting both water lines and the gas supply line to the
heater.
Install the water heater in an area that allows for service and
maintenance access to utility connections, piping, filters, and traps.
Based on the installation location, allow for the following minimum
clearances from the water heater:
References
Descriptions
Minimum
distances
Directly below or adjacent to an
opening; operable windows, doors
and any fresh air openings
48" (USA)
Top
Exhaust Gas
A
B
Intake Air
C
Back
Side
Side
Front
D
From any adjacent wall
12"
E
Below a gutter, sanitary pipework,
eaves or overhang
36"
F
Above ground
12"
G
From a gas meter or gas regulator
36"
Bottom
References
Minimum distances
Bottom
12"
Back
0.5"
Sides
3"
Front
24"
Top
36"
Installation the Outdoor Vent Cover
Downloaded from www.Manualslib.com manuals search engine
153
9.4 Mounting Water Heater
Navien water heaters come with a mounting bracket that is predrilled at 16 inches on center for easy installation on standard wall
studs. If the strength of the wall is insufficient or if the framing is
non-standard or uneven, reinforce the area before installing the
water heater. Avoid installation on common walls as the unit will
make some operational noises while it is running.
2. Align the grooves on the back of the water heater with the
hooks on the mounting bracket and hang the water heater on
the bracket.
To mount the water heater to the wall:
1. Affix the bracket securely to the wall and ensure that it is level
and that it can support the weight of the water heater.
When mounted with the mounting bracket, the water heater
will have a 5/8” (16mm) clearance from the back of the wall.
CAUTION
Do not mount the water heater to dry wall that has not been
reinforced.
154
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
9.5 Ventilation Flow
Intake Air Flow
Exhaust Gas Flow
Installation the Outdoor Vent Cover
Downloaded from www.Manualslib.com manuals search engine
155
9.6 Common Venting
●●
Venting Intake and Exhaust to Dierent Locations
Exhaust
Model : NPE-150S, 180A, 180S, 210A, 210S, 240A, 240S
When cascading the water heaters with other Navien water
heaters, you can install a common venting system. Do not use
common venting if the water heater is used in a cascading system
with other manufacturer’s water heaters. Include a condensate
drain in the main trunk as illustrated in the following examples.
●●
Venting the Exhaust Only (Non-Direct)
Exhaust
Cap
Intake
Condensate
Drain
D
H
W
To determine the size of a common vent:
Cap
1. Add the BTU/H input ratings for each water heater in the
cascading system to determine the total BTU/H rating.
Intake
Condensate
Drain
2. Determine the total length (L) of the common vent, which
consists of the horizontal width (W) and the vertical height (H):
Total length (L) = W + H.
Exhaust
●●
Venting Intake and Exhaust to the Same Location
36" (900mm) min.
D
H
W
Exhaust
Cap
12" (300mm) min.
Intake
Intake
12" (300mm) min.
Condensate
Drain
Cap
Condensate
Drain
3. Refer to the common vent table that follows to determine the
minimum length required for the common vent, based on the
total BTU/H rating, and the diameter of the vent pipe.
NOTE
For each short radius elbow that will be used in the vent, add 8
feet (2.4 m) to the total length. For each long radius elbow that
will be used in the vent, add 5 feet (1.5m) to the total length.
156
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
CAUTION
●●
Regardless of the vent size listed in the table, the connection to the common vent must always be as large as the largest connector. If the
largest connector and the recommended vent are the same size, use the next largest size for the vent.
●●
One short radius elbow = 8 feet, One long radius elbow = 5 feet
Total length (L) = W + H
Required Load
(Total BTU/H)
Model
NPE-180A
NPE-180S
300,000
2
330,000
1
NPE-210A
NPE-210S
360,000
Total length (ft)
NPE-240A
NPE-240S
D= 3"
D=4"
D=5"
D=6"
60(18m)
100(30m)
160(48m)
-
60(18m)
100(30m)
160(48m)
-
1
60(18m)
100(30m)
160(48m)
-
2
60(18m)
100(30m)
160(48m)
-
70(21m)
110(33m)
160(48m)
1
1
398,000
540,000
3
559,000
2
1
70(21m)
110(33m)
160(48m)
578,000
1
2
70(21m)
110(33m)
160(48m)
3
70(21m)
110(33m)
160(48m)
D=5"
D=6"
D=7"
D=8"
597,000
739,000
3
1
80(24m)
120(37m)
-
-
758,000
2
2
80(24m)
120(37m)
-
-
777,000
1
3
80(24m)
120(37m)
-
-
796,000
4
80(24m)
120(37m)
-
-
995,000
5
60(18m)
90(27m)
130(40m)
-
1,194,000
6
-
80(24m)
100(30m)
140(43m)
1,393,000
7
70(21m)
90(27m)
120(36m)
D=7"
D=8"
D=9"
D=10"
1,592,000
8
82(25m)
107(33m)
135(41m)
1,791,000
9
73(22m)
95(29m)
120(37m)
148(45m)
1,990,000
10
65(20m)
85(26m)
108(33m)
133(41m)
2,189,000
11
78(24m)
98(30m)
121(37m)
2,388,000
12
71(22m)
90(27m)
111(34m)
D=9"
D=10"
D=11"
D=12"
2,587,000
13
83(25m)
103(31m)
124(38m)
2,786,000
14
77(23m)
95(29m)
115(35m)
137(42m)
2,985,000
15
72(22m)
89(27m)
108(33m)
128(39m)
3,184,000
16
68(21m)
83(25m)
101(31m)
120(36m)
Installation the Outdoor Vent Cover
Downloaded from www.Manualslib.com manuals search engine
157
10. Installing the H2Air++
10.1.1 Included Items
WARNING
All installation should be done by a qualified expert and in
accordance with the appropriate Navien manual. Installing an
electric appliance with improper methods or materials may
result in serious injury or death due to fire.
The product is supplied with an installation kit. Make sure that the
installation kit contains the following items before installing the
product.
ELECTRICAL SHOCK HAZARD. Disconnect power before
installing or servicing. This can cause severe personal injury,
death, or substantial property damage if ignored.
All wiring must be installed in accordance with local regulations
of the installation site.
When Installing this Product:
1. Read these instructions carefully. Failure to follow them could
damage the product or cause a hazardous condition.
Navien H2Air++
Add-on Controller
Installation Manual
Main Control Connector
(13-pin cable for connection to
NPE-180A/240A water heaters)
Outdoor Temperature Sensor
(with cable)
2. Check the ratings given in the instructions and on the product
to make sure the product is suitable for the application.
3. Installers must be trained, experienced, and licensed service
technicians.
4. Follow local codes for installation and application.
After installation is complete, check the product’s operation by
following the instructions provided in this manual.
NOTE
All wiring must be installed in accordance with local regulations
of the installation site.
10.1 About the H2Air++
Navien H2Air++ is an add-on controller for the Navien
NPE-180A/240A water heaters. It adds input and output functions
to the NPE-180A/240A water heaters for a combination application
where space heating and domestic hot water (DHW) are supplied
simultaneously. With this add-on controller, a thermostat (1 or
2-stage) and an outdoor sensor can be installed along with a
hydronic air handler to add space heating functionality to the
system.
158
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Flow Switch (with cable)
Version 2.21
10.1.2 Specifications
Wiring Connection Table
Refer to the following table for product specifications.
Terminal
Wiring Connection
Items
Specifications
AHU W1
Connect to AHU W1
Model name
KDO-A100
AHU W2
Connect to AHU W2
Device type
Add-on controller for Navien NPE-180A/240A
water heaters
AHU R
Connect to AHU R
Installation
type
Snap-on (onto the NPE-180A/240A water heater
PCB tray)
Flow switch
Flow switch input terminal
T/S W1
Connect to thermostat W1
T/S W2
Connect to thermostat W2
Connections
Main connector socket to water heater
Main control connector (13-pin cable)
Thermostat input terminals
Contacts for one thermostat (1 or 2-stage)
Outdoor sensor connection terminal
Contacts for one outdoor sensor
Output terminal to the air handler unit
Contacts for one AHU (1 or 2-stage)
T/S R
Connect to thermostat R
Outdoor Sensor
Outdoor sensor input
Dip Switch Function Table
10.1.3 CSA P.9 –11 Rating
Combo System
Heat
Generator
Fan Coil
CSHE WHPF
Recovery
Efficiency
TPF
NPE-180A MMVE0S4NAAA 94 (%)
0.96
97 (%)
0.94
NPE-240A MMVE0M4NAAA 95 (%)
0.95
96 (%)
0.95
10.1.4 Device Layout
Refer to the following diagram for the product layout.
SW (DIP 1–4)
ON
OFF
Default
DIP 1
Outdoor reset
not in use
Outdoor reset
in use
OFF
DIP 2
Simultaneous
DHW and
heating*
DHW priority
OFF
DIP 3
2-stage
thermostat using
1-stage
thermostat using
OFF
DIP 4
Reserved
OFF
* Depending on the DHW flow rate (demand), simultaneous DHW and
heating may not be available. When the DHW demand is high, DHW
supply takes priority and the heating may be temporarily turned off until
the DHW demand decreases, even when this function is activated.
10.2 Installing the Device
This section provides information required to install the H2Air++
add-on controller in an NPE-180A/240A water heater.
WARNING
Ensure that you have turned off the power to the water heater
before installing the device.
H2Air++
Downloaded from www.Manualslib.com manuals search engine
159
10.2.1 Basic Principles
The following diagram shows the basic operation of an
NPE-180A/240A water heater system with the H2Air++ add-on
controller.
System Diagram
10.2.2 Installing the Device in an
NPE-180A/240A Water Heater
Follow the instructions to install the Navien H2Air++ in an
NPE-180A/240A water heater.
1. Turn off the power supply to the water heater.
2. Remove the water heater’s front cover by loosening the four
screws securing it to the case.
WARNING
3. Remove the two screws holding the PCB tray in place and pull
out the PCB tray from the unit.
A mixing valve must be installed in the system in order to limit
the DHW output temperature and prevent scalding. Setting
the mixing valve to 115–120°F is recommended.
NOTE
160
●●
Install a spring check valve for vertical pipe runs. Do not use
a swing check valve with vertical piping.
●●
Install either a spring check valve or a swing check valve in a
horizontal pipe run.
●●
An outdoor sensor and a flow switch are supplied with the
product.
●●
Use 18 AWG cables for thermostat wiring.
●●
Install NSF certified mixing valves and expansion tanks ONLY.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
4. Verify the current PCB version of the NPE water heater.
●● For OLD PCB Version KDC-330-5M P12: The PCB must be
replaced with an updated version. Remove all the cables and
connectors from the PCB and replace with the latest PCB
version that is compatible with the H2Air++ kit. Reconnect all
the cables and connectors to the PCB. Proceed to the next
step.
●● For NEW PCB Version KDC-330-5M P20: The existing PCB
can be used. Pull out the PCB from the tray but do NOT
disconnect any cables or wires. Proceed directly to the next
step.
Version 2.21
5. Install the H2Air++ onto the NPE-180A/240A water heater’s PCB
tray. Align the latch at the back of the case with the front lip of
the PCB tray.
10.3 Wiring the Device
This section provides information required to plan and install the
system wiring.
10.3.1 System Wiring Examples
Refer to the following wiring diagrams to properly install wiring for
various setups you may need in your system. Set DIP switch (SW)
#3 as specified for each configuration.
1-Stage Thermostat / 2-Stage Control System
6. Align the two latches at the back of the H2Air+ with the two
catch bars at the back of the water heater’s PCB tray. Then
pivot the H2Air++ onto the PCB tray until the latches snap-on
to the catch bars.
+
7. Connect cables to the H2Air++. For more details, refer to “10.5.2
Entering the R&D Information Menu”, on page 165.
8. Set the proper DIP switches for the desired installation setup.
For more details, refer to “Dip Switch Function Table”, on page
159.
Set DIP switch (SW) #3 to ‘Off’ to configure the system to use a
1-stage thermostat/ 2-stage control.
1-Stage Thermostat / 1-Stage Control System
Set DIP switch (SW) #3 to ‘Off’ to configure the system to use a
1-stage thermostat / 1-stage control.
9. Replace the PCB tray back into the water heater and secure it
with the two screws.
10. Close the front cover and secure it with the 4 screws.
CAUTION
Before disconnecting cables inside the unit, label all cables.
Wiring errors can cause improper operation and dangerous
situations. Verify wiring connections and unit operation after
servicing.
H2Air++
Downloaded from www.Manualslib.com manuals search engine
161
2-Stage Thermostat / 2-Stage Control System
Connecting the Thermostat Cables
Set DIP switch (SW) #3 to ‘On’ to configure the system to use a
2-stage thermostat / 2-stage control.
The H2Air++ receives input signals from thermostats to control the
AHU. Insert the fork connector into the contact. Then tighten the
terminal screw with a screwdriver.
10.3.2 Cable Connections
Follow the instructions below to connect the cables to the H2Air++.
Connecting the Outdoor Temperature Sensor
Cable
Connecting the Flow Switch Cables
Insert the fork connector into the contact. Then tighten the
terminal screw with a screwdriver.
An outdoor temperature sensor is supplied with the Navien
H2Air++ installation kit. Insert the exposed wire into the terminal.
Then tighten the terminal screw with a screwdriver.
NOTE
162
●●
Use thermostat wire (18 gauge wire) for the outdoor
temperature sensor connection.
●●
When installing the outdoor temperature sensor, avoid
installing it in direct sunlight.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Connecting the Main Control Connector
10.4 Configuring the Device
To connect the H2Air++ to the Navien NPE-180A/240A water
heater, use the 13-pin main control connector supplied with the
Navien H2Air++. Connect one end of the cable to the connector
socket on the H2Air++ PCB. Then, connect the other end to the
connector socket on the NPE-180A/240A water heater PCB.
This section provides the information required to set the desired
options for the NPE-180A/240A water heater system with the
H2Air++ add-on controller.
10.4.1 Pump Control Options
CAUTION
The drawings in this instruction are intended only as a guide
and are not replacements for professional engineering
drawings. This drawing represents a concept system and
does not imply compliance with local building codes. Actual
installation requirements may vary depending on installation
locations and parameters. All installation work must be carried
out in accordance with all local building codes. Verify with local
building officials before commencing system installation.
The following example demonstrates the application of pump
control configuration options.
A System with the Internal Circulation Pump
Set the 2-way valve inside the water heater to ‘EXT’. For more
information about settings, refer to “Selecting a Recirculation
Mode (“A” model only)” in the Water Heater Installation Manual.
WARNING
An anti-scalding device must be installed in the system in order
to limit the DHW output temperature and prevent scalding.
Setting the valve to 115-120°F is recommended.
H2Air++
Downloaded from www.Manualslib.com manuals search engine
163
NOTE
●●
Install a spring check valve for vertical pipe runs. Do not use
a swing check valve with vertical piping.
●●
Install either a spring check valve or a swing check valve for
a horizontal run.
●●
An outdoor sensor and a flow switch are supplied with the
product.
●●
Use 18 AWG wires for thermostat installation.
●●
Install certified mixing valves and expansion tanks ONLY.
10.4.2 DHW Priority Options
Refer to the following options to configure the system’s DHW
supply modes.
DHW Priority Mode
When the system is configured for the DHW priority mode, space
heating does not operate if there is DHW demand (the flow switch
is ‘closed’).
This section provides information required to properly configure
the NPE-180A/240A water heater to setup and utilize the functions
provided by the H2Air++ add-on controller.
10.5.1 Entering the Service Information
Mode
Follow the instructions below to access the Service information
mode.
1. At <Normal operation mode>, press the [Diagnostic] button
once to access the service information screen.
2. If you press the [+] / [-] button, the value for the selected
item is increased or decreased. Then, the adjusted value is
displayed.
3. The currently-selected information data item is identified
with an alphabet character prefix followed by 3 digits of the
relevant data.
4. Press the [Reset] button once to return to <Normal operation
mode>.
Set the DIP switch (SW) #2 to ‘Off’ to configure the
system to operate in the DHW priority mode.
ON
1
10.5 Configuring the NPE-180A/240A
Water Heater
2
3
4
NOTE
If no buttons are pressed for 1 hour, then it automatically
returns to the <Normal operation mode>.
Simultaneous DHW and Space Heating Mode
When the system is configured for simultaneous DHW and Space
heating mode, both DHW and space heating will be supplied at
the same time. However, when DHW demand becomes high, the
system automatically turns off the space heating. The system will
continue in this mode until it determines that DHW demand has
reduced from high demand to moderate or low demand.* Please
see appendix for water heater performance specifications.
Item
(T) Outdoor
temperature
* The system determines that DHW demand is high and stops supplying
the space heating when: - the water heater is running at or above 85% of
its maximum capacity.
ON
1
164
2
3
4
Set the DIP switch (SW) #2 to ‘On’ to configure the
system to operate DHW and space heating mode
simultaneously.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
(U) Heating
temperature
based on
the outdoor
temperature
Description
Displays
current
outdoor
temperature
Displays
the heating
temperature
based on
the current
outdoor
temperature
Display
Outdoor
reset OFF
(Dip switch
#1 ‘ON’)
Outdoor
reset
On(Dip
switch #1
‘OFF’) eg.)
50°F
Outdoor
reset OFF
(Dip switch
#1 ‘ON’)
Outdoor
reset
On(Dip
switch #1
‘OFF’) eg.)
120°F
Version 2.21
10.5.2 Entering the R&D Information Menu
No.
Mode
This section describes how to enter the R&D information mode to
configure various parameters and control system functions.
9
CH MIN Set-point
Entering the R&D Information Menu
10
CH MAX Set-point
11
2-Stage T/S Output Heat-Capacity
Display
Follow the instructions below to enter the R&D information menu.
1. On the Front panel, press the Power button to turn off the
water heater.
2. Enter the R&D information menu by pressing the Up (+) button
three times, the Down (-) button three times, and then the Up
(+) button four more times.
10.5.4 Configuring Water Heater Functions
3. In the R&D information menu, use the Up (+) or Down (-)
buttons to move to 2.PAR (Parameter information mode), and
then press the Info button.
This section describes the water heater functions and provides the
information required to configure the parameters for the desired
operation.
No.
Mode
1
Technical Information
2
Parameter Information
Display
The pump exercise function is designed to prevent the stagnation
of hot water in the heating system.
The pump exercise function operates every 24 hours. Pump
exercise operation time function sets the desired pump exercise
operation time differently depending on the plumbing as well as
environmental conditions.
4. To return to the previous menu (R&D information menu), press
the [Reset] button once.
10.5.3 Parameter Table
The following table lists the parameters used to configure the
water heater system functions.
No.
Mode
4
Pump Exercise Operation Time
5
Burn Delay Time
6
Pump Post Purge Time
7
Outdoor Low Temperature Set-point
8
Outdoor High Temperature Set-point
Pump Exercise Operation Time (P04)
Display
With this option activated, the NPE-180A/240A water heater
monitors the pump operation. When it detects that a pump
has not been used for a specific period, it runs the pump for a
set duration. If the flow rate is not detected while the pump is
operating, the ‘E438’ error message is displayed.
To change the pump exercise operation time:
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.04. Then, press the Info button to
enter the Pump exercise operation time mode.
2. In the Pump exercise operation time mode, use the Up (+)
or Down (-) buttons to change the value and press the Info
button to set to the desired mode.
Range
Description
1–240(sec)
Sets the exercise operation time
(default: 30 sec)
Display
H2Air++
Downloaded from www.Manualslib.com manuals search engine
165
Pump Post Purge Time (P.06)
NOTE
●●
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
●●
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
●●
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
●●
While the pump is excising, the burner will not fire.
This function is used to set the post purge time after a combustion
cycle is completed.
To change the pump post purge time:
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.06. Then, press the Info button to
enter the Pump post purge time mode.
2. In the Pump post purge time mode, use the Up (+) or Down (-)
buttons to change the value and press the Info button to set to
the desired mode.
Range
Description
Burn Delay Time (P.05)
0
Pump post purge time
unavailable
This function is used to set the burner delay time at an optimal
value for the air handler application. If there is no burner delay
time, the water heater might turn on or off once or twice during
the air handler delay time.
1–120 (sec)
Sets the pump post purge time
when heating stops in a system
(default: 30 sec).
Display
To change the burner delay time:
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.05. Then, press the Info button to
enter the Burn delay time mode.
2. In the Burn delay time mode, use the Up (+) or Down (-)
buttons to change the value and press the Info button to set to
the desired mode.
Range
Description
0
Burn delay time unavailable
1–120 (sec)
Sets the pump ON delay time
when the heating is turned on
(default: 30 sec).
Display
NOTE
●●
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
●●
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
●●
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
NOTE
166
●●
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
●●
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
●●
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Outdoor Reset Control (P07–P10)
Outdoor Low Temperature Set-point (P.07)
The Outdoor Reset Control feature can be used to enhance energy
efficiency while maintaining optimal heating performance.
Outdoor Reset Control automatically changes the space heating
temperature setting based on the outdoor temperature and the
current space heating system application (system load).
To change the outdoor low temperature set-point:
To achieve optimal heating performance, configure the following
set-points: the Outdoor Low Temperature, the Outdoor High
Temperature, the heating MIN and the heating MAX Set-point
configuration must be based on the H2Air++ system characteristics
and installation environment.
2. In the Outdoor low temperature set-point mode, use the Up
(+) or Down (-) buttons to change the value and press the Info
button to set to the desired mode.
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.07. Then, press the Info button to
enter the Outdoor low temperature set-point mode.
Item
Description
Refer to the following examples in the graph to configure the
Outdoor Reset Control feature.
●●
Outdoor low
temperature
set-point
●●
●●
Unavailable
Display
Sets the outdoor low
temperature set-point
when outdoor reset is ON
(DIP switch #1 ‘OFF’)
(default: 14°F (-10°C))
Range: -4°F (-20°C) – 59°F
(15°C)
Cannot be greater than the
[Outdoor high temperature
set-point -9°F (5°C)]
Outdoor reset is OFF (DIP
switch #1 ‘ON’)
NOTE
* The graph above is an example of a few possible outdoor reset parameter
settings. For more information about settings, refer to the following
information.
* If the Outdoor Reset On (DIP switch #1 OFF) is set and the outdoor
temperature sensor is not connected, or the outdoor temperature sensor
value is outside the normal range, the ‘740’ error message is displayed and
the system operates the same way as with the Outdoor Reset OFF (DIP
switch #1 ON) setting..
●●
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
●●
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
●●
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
H2Air++
Downloaded from www.Manualslib.com manuals search engine
167
Outdoor High Temperature Set-point (P.08)
Heating MIN Set-point (P.09)
To change the outdoor high temperature set-point:
To change the heating MIN set-point:
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.08. Then, press the Info button to
enter the Outdoor high temperature set-point mode.
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.09. Then, press the Info button to
enter the Heating MIN set-point mode.
2. In the Outdoor high temperature set-point mode, use the Up
(+) or Down (-) buttons to change the value and press the Info
button to set to the desired mode.
2. In the Heating MIN set-point mode, use the Up (+) or Down (-)
buttons to change the value and press the Info button to set to
the desired mode.
Item
Description
●●
Outdoor
high
temperature
set-point
●●
●●
Unavailable
Display
Sets the outdoor high
temperature set-point when
outdoor reset is ON
(DIP switch #1 ‘OFF’)
(default: 70°F (21°C))
Range: 5°F (-15°C) – 104°F
(40°C)
Cannot be lower than the
[Outdoor low temperature
set-point + 9°F (5°C)]
Outdoor reset is OFF (DIP
switch #1 ‘ON’)
NOTE
168
Item
Description
●●
Heating MIN
set-point
●●
●●
Unavailable
Display
Sets the Heating MIN setpoint when outdoor reset
is ON (DIP switch #1 ‘OFF’)
(Default: 100°F (37.5°C))
Range: 100°F (37.5°C) –
140°F (60°C)
Cannot be greater than the
[CH MAX set-point - 36°F
(20°C)]
Outdoor reset is OFF (DIP
switch #1 ‘ON’)
NOTE
●●
●●
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
●●
●●
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
●●
●●
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21
Heating MAX Set-point (P.10)
2-Stage T/S Output Heat-Capacity (P.11)
To change the heating MAX set-point:
Models with the 2-stage air handler control function (W1, W2) can
use a 2-stage thermostat or can be automatically controlled by the
H2Air++ controller (If the DIP switch # 3 is OFF).
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.10. Then, press the Info button to
enter the Heating MAX set-point mode.
2. In the Heating MAX set-point mode, use the Up (+) or Down (-)
buttons to change the value and press the Info button to set to
the desired mode.
Item
Description
●●
Heating
MAX setpoint
●●
●●
Display
Sets the Heating MAX Setpoint when outdoor reset
is ON (DIP switch #1 ‘OFF’)
(Default: 180°F (82°C))
Range: 136°F (57.5°C) –
180°F (82°C)
Cannot be lower than the
[CH MIN set-point + 36°F
(20°C)]
When using the automatic 2-stage heating feature, the system will
modulate between the 1-stage and 2-stage based on the set heat
capacity parameter of the water heater. This heat capacity value
can be adjusted based on the desired modulation point (default
heat capacity is 25%)
To change the 2-stage T/S output heat-capacity:
1. In the Parameter information time mode, use the Up (+) or
Down (-) buttons to select P.11. Then, press the Info button to
enter 2-stage T/S output heat-capacity mode.
2. In the 2 stage T/S output heat-capacity mode, use the Up (+)
or Down (-) buttons to change the value and press the Info
button to set to the desired mode.
Item
Description
●●
Unavailable
Outdoor reset is OFF (DIP
switch #1 ‘ON’)
Min heat
capacity –
100% (by
0.5% )
NOTE
●●
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
●●
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
●●
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
Unavailable
●●
Display
Sets the standard
modulating heat capacity
value between 1-stage and
2-stage heating operation
2-stage T/S OFF (DIP switch
#3 ‘OFF’)
2-stage T/S ON (DIP switch #3
‘ON’)
NOTE
●●
If no buttons are pressed for 10 seconds or if the Info
button is pressed, the current parameter value will be saved
automatically.
●●
To return to the <PARAMETER INFORMATION MENU MODE>,
press the [Reset] button once.
●●
If no buttons are pressed for five minutes, the display will
automatically return to the <PARAMETER INFORMATION
MENU MODE>.
H2Air++
Downloaded from www.Manualslib.com manuals search engine
169
The Navien NPE-180A and NPE-240A water heaters that are used
in the DHW/heating systems should be properly maintained
and flushed on an annual basis. Please see the NPE Water Heater
Service Manual for more details regarding annual servicing and
maintenance.
10.7 Appendix
This section provides additional information to be considered
when you design a hydronic system using an NPE-180A/240A
water heater.
10.7.3 NPE-180A/240A Pump P-Q Curve
23%WTXG
ft
m
*GCF
HVO
10.6 Maintenance
(NQY
)2/
10.7.1 NPE-180A/240A Pressure Drop
Curve
NOTE
●●
When the system uses an internal circulation pump with
the NPE-180A/240A water heaters, the flow rate may vary
depending on the type and capacity of the AHU in use.
●●
If the system uses an internal circulation pump with the
NPE-180A/240A water heaters or pumps manufactured by
SunTherm corporation (MMVE0S4NAAA, MMVE0M4NAAA),
the flow rate will be approximately 3 GPM.
10.7.2 NPE-180A/240A Flow Rate Graph
170
NPE Service Manual
Downloaded from www.Manualslib.com manuals search engine
Version 2.21